==================================BSR21================================== 21. Association of free fatty acids with phospholipid bilayers. Fatty acids- aqueous phase, hydrated fatty acids (Fatty acids associated with water). Ionization of fatty acids to acid-soaps. 1 UI - 87111863 AU - Takagi M ; Higashioka H ; Morita N TI - Effects of lipophilic derivatives of L-ascorbic acid and dehydro-L-ascorbic acid on the peroxidation of linoleic acid in neutral phosphate buffer containing alcohol. AB - 6-O-Palmitoyl-AsA (AP) and -DHA (DHAP) suppressed LA peroxidation considerably in both 10% and 20% EtOH solutions. The duration of the suppression of LA peroxidation was longer with AP than with DHAP. But after the initial suppression of LA peroxidation, both derivatives showed an accelerating effect. 6-O-Acetyl-AsA (Ac-AsA) and -DHA (Ac-DHA) accelerated LA peroxidation from the start of the reaction in 10% EtOH, but suppressed it notably in 20% EtOH. 4-Phenyl-2,3-dihydroxy-2-buten-4-olide (PDHB) and 4-phenyl-2,3-dioxo-4-butenolide (PDOB) accelerated LA peroxidation in 10% EtOH. With 20% EtOH solution, PDHB suppressed LA peroxidation notably, as did AP, but PDOB showed only a short duration (about 1 h) of suppression. These results suggest the complexity of LA peroxidation catalyzed by lipophilic AsA or DHA in aqueous solution containing alcohol. MH - *Alcohol, Ethyl ; Ascorbic Acid/*ANALOGS & DERIVATIVES/PHARMACODYNAMICS ; Buffers ; Dehydroascorbic Acid/*PHARMACODYNAMICS ; *Linoleic Acids ; *Lipid Peroxides ; Oxidation-Reduction ; Phosphates ; 4-Butyrolactone/ ANALOGS & DERIVATIVES/PHARMACODYNAMICS SO - J Nutr Sci Vitaminol (Tokyo) 1986 Aug;32(4):389-94 2 UI - 87101036 AU - Froud RJ ; East JM ; Rooney EK ; Lee AG TI - Binding of long-chain alkyl derivatives to lipid bilayers and to (Ca2+-Mg2+)-ATPase. AB - Binding constants for myristoleic, palmitoleic, palmitic, oleic, and eicosanoic acids and oleyland stearylamine to lipid bilayers have been determined by using microelectrophoresis. Quenching of the fluorescence of the hydrophobic tryptophan analogue N-palmitoyl-L-tryptophan n-hexyl ester incorporated into lipid bilayers by oleic acid and oleylamine and their brominated derivatives is interpreted in terms of unlimited binding to the bilayers. The tryptophan fluorescence of the (Ca2+-Mg2+)-ATPase purified from sarcoplasmic reticulum is quenched when reconstituted into bilayers of 1,2-bis(9,10-dibromostearoyl)-phosphatidylcholine (BRPC). Addition of fatty acids, oleylamine, oleyl alcohol, and methyl oleate to the ATPase reconstituted with BRPC reduces the quenching caused by BRPC, indicating binding of these molecules at the lipid-protein interface (annular sites). The charged molecules bind more strongly at the annular sites than do the uncharged molecules. Additional quenching of BRPC-ATPase by brominated derivatives of these molecules indicates binding at sites distinct from the lipid-protein interface, with binding constants similar to those for binding at annular sites, except for oleylamine. Quenching of tryptophan fluorescence of the ATPase by fatty acids and oleylamine suggests that ca. 50% of the tryptophan residues of the ATPase are located close to the lipid-water interface of the membrane. MH - Adenosine Triphosphatase, Calcium/*METABOLISM ; Adenosine Triphosphatase, Magnesium/*METABOLISM ; Animal ; *Fatty Acids/METABOLISM ; Hydrogen-Ion Concentration ; Kinetics ; *Lipid Bilayers ; Muscles/ENZYMOLOGY ; *Phosphatidylcholines ; Protein Binding ; Rabbits ; Structure-Activity Relationship ; Support, Non-U.S. Gov't ; Tryptophan/ANALOGS & DERIVATIVES SO - Biochemistry 1986 Nov 18;25(23):7535-44 3 UI - 87098794 AU - Maiorino M ; Roveri A ; Gregolin C ; Ursini F TI - Different effects of Triton X-100, deoxycholate, and fatty acids on the kinetics of glutathione peroxidase and phospholipid hydroperoxide glutathione peroxidase. AB - The effects of Triton X-100, deoxycholate, and fatty acids were studied on the two steps of the ping-pong reaction catalyzed by Se-dependent glutathione peroxidases. The study was carried out by analyzing the single progression curves where the specific glutathione oxidation was monitored using glutathione reductase and NADPH. While the "classic: glutathione peroxidase was inhibited only by Triton, the newly discovered "phospholipid hydroperoxide glutathione peroxidase: was inhibited by deoxycholate and by unsaturated fatty acids. The kinetic analysis showed that in the case of glutathione peroxidase only the interaction of the lipophilic peroxidic substrate was hampered by Triton, indicating that the enzyme is not active at the interface. Phospholipid hydroperoxide glutathione peroxidase activity measured with linoleic acid hydroperoxide as substrate, on the other hand, was not stimulated by the Triton concentrations which have been shown to stimulate the activity on phospholipid hydroperoxides. Furthermore a slight inhibition was apparent at high Triton concentrations and the effect could be attributed to a surface dilution of the substrate. Deoxycholate and unsaturated fatty acids were not inhibitory on glutathione peroxidase but inhibited both steps of the peroxidic reaction of phospholipid hydroperoxide glutathione peroxidase, in the presence of either amphiphilic or hydrophilic substrates. This inhibition pattern suggests an interaction of anionic detergents with the active site of this enzyme. These results are in agreement with the different roles played by these peroxidases in the control of lipid peroxide concentrations in the cells. While glutathione peroxidase reduces the peroxides in the water phase (mainly hydrogen peroxide), the new peroxidase reduces the amphyphilic peroxides, possibly at the water-lipid interface. MH - Binding Sites ; Catalysis ; Comparative Study ; Deoxycholic Acid/ *PHARMACODYNAMICS ; Fatty Acids/*PHARMACODYNAMICS ; Glutathione Peroxidase/ANTAGONISTS & INHIBITORS/*METABOLISM ; Kinetics ; Linoleic Acids/METABOLISM ; Lipid Peroxides/METABOLISM ; Oleic Acids/ PHARMACODYNAMICS ; Polyethylene Glycols/*PHARMACODYNAMICS ; Substrate Specificity SO - Arch Biochem Biophys 1986 Dec;251(2):600-5 USER: 4 UI - 87076616 AU - Fern:andez MS ; Gonz:alez-Mart:inez MT ; Calder:on E TI - The effect of pH on the phase transition temperature of dipalmitoylphosphatidylcholine-palmitic acid liposomes. AB - The shift in the gel-liquid crystal phase transition temperature (tm) of dipalmitoylphosphatidylcholine liposomes induced by incorporation of 10 mol% palmitic acid, was measured by 90 degrees light scattering at different bulk pH values. It has been found that the tm shift decreases sigmoidally from 4.7 to -0.3 degrees C as the bulk pH is raised from 5 to 11. Since it is in this range that the carboxyl group of a membrane-bound fatty acid should ionize, our results can be interpreted to mean that there is relationship between the tm shift and the degree of dissociation of palmitic acid, the uncharged fatty acid increasing tm and its conjugate, anionic form, slightly decreasing the transition temperature of dipalmitoylphosphatidylcholine liposomes. The experimental results are fitted by a modified form of the Henderson-Hasselbach equilibrium expression which takes into account the effect of the anionic fatty acid on the surface potential and hence, on the surface pH of liposomes, according to Gouy-Chapman and Boltzmann equations, respectively. Best fit between theory and experiments is found when the intrinsic interfacial pK of palmitic acid is set equal to 7.7. This high pK value can be explained as due to the effect of the lower dielectric constant of the interfacial region, as compared to bulk water, on the acid-base dissociation of the carboxyl group. The results presented here show that upon incorporation of palmitic acid, the phase transition of dipalmitoylphosphatidylcholine bilayers becomes extremely sensitive to changes of pH in the vicinity of the physiological range. This property is not shown by the pure phospholipid bilayers in the same pH range. MH - Hydrogen-Ion Concentration ; Light ; *Liposomes ; *Palmitic Acids ; Scattering, Radiation ; Support, Non-U.S. Gov't ; Temperature ; *1,2-Dipalmitoylphosphatidylcholine SO - Biochim Biophys Acta 1986 Dec 16;863(2):156-64 5 UI - 87054645 AU - Navar LG ; Paul RV ; Carmines PK ; Chou CL ; Marsh DJ TI - Intrarenal mechanisms mediating pressure natriuresis: role of angiotensin and prostaglandins. AB - The ability of the kidney to increase sodium and water excretion in response to increases in perfusion pressure has been recognized for more than 50 years. Because glomerular filtration rate is tightly autoregulated, pressure natriuresis occurs as the result of decreased tubular sodium reabsorption rather than increased filtered load. Micropuncture and microperfusion data support the contention that acute changes in arterial pressure can alter proximal tubule reabsorption; however, studies have failed to show a consistent association between changes in sodium excretion and peritubular, interstitial, or tubular pressures. Thus, the specific intrarenal mechanism for the change in tubular reabsorption in response to an acute change in arterial pressure does not appear to be related to the peritubular physical factors at the level of outer cortical nephrons. The possible roles of angiotensin and prostaglandins as humoral mediators of pressure natriuresis are considered in this report. Although angiotensin II is a powerful modulator of the slope of the pressure natriuresis relationship, the responsiveness of sodium excretion to arterial pressure is actually enhanced by angiotensin-converting enzyme inhibitors. These data suggest that angiotensin does not mediate the basic phenomenon. Recent experiments indicate that intrarenal prostaglandins also modulate the magnitude of the pressure natriuresis relationship, but these hormones do not appear to be essential for its basic manifestation. MH - Absorption ; Angiotensin II/*PHYSIOLOGY ; Animal ; *Blood Pressure ; Human ; Kidney Tubules, Proximal/PHYSIOLOGY ; Kidney/BLOOD SUPPLY/ *PHYSIOLOGY ; *Natriuresis ; Prostaglandins/*PHYSIOLOGY ; Renin-Angiotensin System ; Review ; Support, U.S. Gov't, P.H.S. SO - Fed Proc 1986 Dec;45(13):2885-91 6 UI - 87049759 AU - Connor J ; Norley N ; Huang L TI - Biodistribution of pH-sensitive immunoliposomes. AB - Liposomes composed of either dioleoylphosphatidylethanolamine and oleic acid (pH-sensitive) or dioleoylphosphatidylcholine and oleic acid (pH-insensitive) were injected into C3H and Balb/c mice in order to determine the tissue distribution of both the lipid and the aqueous content. The lipid component was monitored by use of [3H]cholestanyl ether and the aqueous content was monitored by use of encapsulated 125I-tyraminyl-inulin. The pH-insensitive liposomes injected into both types of mice were rapidly cleared from the blood stream followed by accumulation primarily in the liver, followed by the spleen. The presence of a monoclonal antibody on the liposome surface caused a slight acceleration in liver accumulation, though generally gave the same profile as the antibody-free liposomes. pH-sensitive liposomes were leaky upon exposure to the mouse plasma following injection. The lipid component, though, displayed a large amount (e.g., 50-70% in C3H mice) of accumulation in the lung for up to 6 h, followed by a subsequent appearance in the liver and spleen. The presence of monoclonal antibody had no effect on the tissue distribution profile. These results indicate that the pH-sensitive liposomes, although ineffective as an aqueous drug delivery agent, may be effective as a means of delivering lipophilic drugs to the lung. MH - Animal ; Antibodies, Monoclonal/*ADMINISTRATION & DOSAGE ; Hydrogen-Ion Concentration ; Inulin/ANALOGS & DERIVATIVES ; Iodine Radioisotopes ; Liposomes/*ADMINISTRATION & DOSAGE ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C3H ; Oleic Acids/*ADMINISTRATION & DOSAGE ; Phosphatidylcholines/ *ADMINISTRATION & DOSAGE ; Phosphatidylethanolamines/*ADMINISTRATION & DOSAGE ; Support, U.S. Gov't, P.H.S. ; Tissue Distribution SO - Biochim Biophys Acta 1986 Dec 10;884(3):474-81 7 UI - 87049749 AU - Turk J ; Wolf BA ; Lefkowith JB ; Stump WT ; McDaniel ML TI - Glucose-induced phospholipid hydrolysis in isolated pancreatic islets: quantitative effects on the phospholipid content of arachidonate and other fatty acids. AB - Our recent findings indicate that glucose-induced insulin secretion from isolated pancreatic islets is temporally associated with accumulation of substantial amounts of free arachidonic acid and that arachidonate may serve as a second messenger for intracellular calcium mobilization in islets. In an effort to determine the source of this released arachidonate, the endogenous fatty acid composition of phospholipids from islets has been determined by thin-layer chromatographic separation of the phospholipids, methanolysis to the fatty acid methyl esters, and quantitative gas chromatographic analyses. The relative abundance of phospholipids in islets as judged by their fatty acid content was phosphatidylcholine (PC), 0.63; phosphatidylethanolamine (PE), 0.23; phosphatidylinositol (PI), 0.067; phosphatidylserine (PS), 0.049. Arachidonate constituted 17% of the total islet fatty acid content, and PC contained 43% of total islet arachidonate. Islets incubated with [3H]arachidonate in the presence of 28 mM D-glucose incorporated radiolabel into PC with a considerably higher specific activity than that of PE, PS or PI. The total fatty acid content of PC from islets incubated with 28 mM glucose for 30 min was significantly lower than that of islets incubated with 3 mM glucose, and smaller effects were observed with PE, PS and PI. The molar decrement in PC arachidonate was 3.2 pmol/islet under these conditions, which is sufficient to account for the previously observed accumulation of free arachidonate (2 pmol/islet). A sensitive method involving negative ion-chemical ionization-mass spectrometric analyses of the pentafluorobenzyl esters of fatty acids derived from trace amounts of lysophosphatidylcholine (lyso-PC) was developed, and glucose-stimulation was found to reduce islet lyso-PC content by about 10-fold. These findings indicate that the insulin secretagogue D-glucose induces phospholipid hydrolysis in islets and suggest that PC may be the major source of free arachidonate which accumulates in glucose-stimulated islets. MH - Animal ; Arachidonic Acids/*METABOLISM ; Cells, Cultured ; Fatty Acids/ *METABOLISM ; Glucose/*PHARMACODYNAMICS ; Hydrolysis ; In Vitro ; Islands of Langerhans/DRUG EFFECTS/*METABOLISM ; Kinetics ; Male ; Phospholipids/ *METABOLISM ; Rats ; Rats, Inbred Strains ; Support, U.S. Gov't, P.H.S. SO - Biochim Biophys Acta 1986 Dec 5;879(3):399-409 8 UI - 87049619 AU - Ho RJ ; Rouse BT ; Huang L TI - Target-sensitive immunoliposomes: preparation and characterization. AB - A novel target-sensitive immunoliposome was prepared and characterized. In this design, target-specific binding of antibody-coated liposomes was sufficient to induce bilayer destabilization, resulting in a site-specific release of liposome contents. Unilamellar liposomes were prepared by using a small quantity of palmitoyl-immunoglobulin G (pIgG) to stabilize the bilayer phase of the unsaturated dioleoylphosphatidylethanolamine (PE) which by itself does not form stable liposomes. A mouse monoclonal IgG antibody to the glycoprotein D of Herpes simplex virus (HSV) and PE were used in this study. A minimal coupling stoichiometry of 2.2 palmitic acids per IgG was essential for the stabilization activity of pIgG. In addition, the minimal pIgG to PE molar ratio for stable liposomes was 2.5 X 10(-4). PE immunoliposomes bound with HSV-infected mouse L929 cells with an apparent Kd of 1.00 X 10(-8) M which was approximately the same as that of the native antibody. When 50 mM calcein was encapsulated in the PE immunoliposomes as an aqueous marker, binding of the liposomes to HSV-infected cells resulted in a cell concentration dependent lysis of the liposomes as detected by the release of the encapsulated calcein. Neither uninfected nor Sendai virus infected cells caused a significant amount of calcein release. Therefore, the release of calcein from PE immunoliposomes was target specific. Dioleoylphosphatidylcholine immunoliposomes were not lysed upon contact with infected cells under the same conditions, indicating that PE was essential for the target-specific liposome destabilization.(ABSTRACT TRUNCATED AT 250 WORDS) MH - Animal ; Cell Transformation, Viral ; Deoxycholic Acid ; Herpesvirus Hominis/GENETICS ; *IgG ; L Cells/METABOLISM ; Lipid Bilayers ; *Liposomes ; Mice ; *Palmitic Acids ; Para-Influenza Virus Type 1/ GENETICS ; Peptide Hydrolases/METABOLISM ; *Phosphatidylcholines ; *Phosphatidylethanolamines ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. ; Tritium SO - Biochemistry 1986 Sep 23;25(19):5500-6 9 UI - 87017195 AU - Brash AR ; Ingram CD TI - Lipoxygenase metabolism of endogenous and exogenous arachidonate in leukocytes: GC-MS analyses of incubations in H2(18)O buffers. AB - Fatty acids are labeled with 18O in the carboxyl group during ester hydrolysis in H2(18)O. We utilized this principle to develop a novel mass spectrometric method for study of the turnover of arachidonic acid in intact cell systems. Analysis of 18O incorporations was by negative ion chemical ionization GC-MS. The use of deuterium-labeled exogenous substrates allowed the metabolic fate of exogenous and intrinsic compounds to be distinguished. Thus, it was shown that the preferred route of 5-lipoxygenase metabolism of exogenous arachidonic acid in ionophore-stimulated human neutrophils is via direct reaction with the enzyme and not via incorporation into cellular lipids. The re-uptake of 5-HETE was also studied. For investigation of intracellular reactions which involve ester hydrolysis, the 18O labeling method is unique in providing direct evidence of the intermediate metabolic pathway of endogenous and exogenous products associated with the arachidonic acid cascade. MH - A-23187/PHARMACODYNAMICS ; Arachidonic Acids/ADMINISTRATION & DOSAGE/ *METABOLISM ; Deuterium/DIAGNOSTIC USE ; Esters ; Human ; Hydrolysis ; Hydroxyeicosatetraenoic Acids/ANALYSIS/METABOLISM ; Lipoxygenases/ *METABOLISM ; Mass Fragmentography ; Neutrophils/*METABOLISM ; Support, U.S. Gov't, P.H.S. SO - Prostaglandins Leukotrienes Med 1986 Aug;23(2-3):149-54 10 UI - 87013827 AU - Tarapoom N ; Royce R ; Yorio T TI - Inhibition of the antidiuretic hormone hydroosmotic response by phospholipids and phospholipid metabolites. AB - Phospholipid metabolities and phospholipids containing arachidonic acid (AA) inhibited the antidiuretic hormone (ADH)-induced increase in transepithelial water flow in the toad urinary bladder, but had no effect on basal water flow when added to the serosal bathing solution. Other fatty acid-substituted phospholipid metabolites had no effect on osmotic water movement in the presence or absence of ADH. Indomethacin attenuated the inhibitory effects of the AA containing phospholipid metabolities (PMAA), suggesting that the PMAA response required AA release and prostaglandin (PG) formation. PMAA increased PGE formation as measured by radioimmunoassay. PG have been reported to inhibit ADH-stimulated water flow by inhibiting adenylcyclase. PGE2 (10(-8) M) had no effect on cyclic AMP-stimulated water flow, whereas exogenous AA and PMAA attenuated the hydroosmotic response to added cyclic AMP. Indomethacin only partially reversed the inhibition by AA of the cyclic AMP-associated water movement, suggesting that the inhibition by AA and PMAA may involve other metabolites of AA than PG. PG and the AA cascade have been implicated as cellular modulators of the ADH hydroosmotic response. The present results offer additional support to the theory that this system may regulate the intracellular events that are transduced following receptor activation by ADH. MH - Adenosine Cyclic Monophosphate/PHARMACODYNAMICS ; Animal ; Arachidonic Acids/*PHARMACODYNAMICS ; Argipressin/ANTAGONISTS & INHIBITORS/ *PHARMACODYNAMICS ; Bladder/DRUG EFFECTS/*PHYSIOLOGY ; Body Water/ METABOLISM ; Bufo Marinus ; Epithelium/DRUG EFFECTS/PHYSIOLOGY ; In Vitro ; Indomethacin ; Osmolar Concentration ; Phospholipids/*PHARMACODYNAMICS ; Structure-Activity Relationship ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. SO - Lipids 1986 Sep;21(9):596-602 11 UI - 87005916 AU - Okun IM ; Merezhinskaya NV ; Rakovich AA ; Volkovets TM ; Aksentsev SL ; Konev SV TI - Inactivation of muscarinic acetylcholine receptors in brain synaptic membranes by free fatty acids. Evaluation of the role of lipid phase. AB - Arachidonic, linolenic and linoleic acids decreased the binding of the m-cholinergic antagonist [3H] QNB and did not affect the ratio of high to low affinity binding sites to the agonist carbamoylcholine in rat brain synaptic membranes. In the presence of arachidonic acid, SH-reagent N-ethylmaleimide acquired the ability to block QNB binding to receptor. Lipids in the bilayer and annular regions were probed by fluorescence of 1,6-diphenyl-1, 3, 5-hexatriene and pyrene. A microviscosity drop induced by increasing temperature from 10 to 37 degrees C did not affect the level of QNB equilibrium binding, whereas arachidonic acid strongly inhibited the binding at concentrations inducing the same drop in microviscosity as that induced by heating. For various unsaturated fatty acids an equal extent of receptor blocking was reached at quite different degrees of bilayer fluidization, the state of annular lipid being not changed under these conditions. It is suggested that the effect of unsaturated acids is reached through their direct interaction with the receptor, which undergoes a conformational change, rather than by an alteration of the physical state of the lipid phase of the membrane. MH - Animal ; *Brain Chemistry ; Carbachol/METABOLISM ; Fatty Acids, Nonesterified/*PHARMACODYNAMICS ; Lipid Bilayers/METABOLISM ; Membrane Fluidity/DRUG EFFECTS ; Membrane Lipids/*PHYSIOLOGY ; Quinuclidinyl Benzilate/METABOLISM ; Rats ; Receptors, Muscarinic/*DRUG EFFECTS ; Spectrometry, Fluorescence ; Synaptic Membranes/*METABOLISM SO - Gen Physiol Biophys 1986 Jun;5(3):243-58 12 UI - 86250481 AU - Selig WM ; Noonan TC ; Kern DF ; Malik AB TI - Pulmonary microvascular responses to arachidonic acid in isolated perfused guinea pig lung. AB - We examined the effects of arachidonic acid (AA) on pulmonary hemodynamics and fluid balance in Ringer- and blood-perfused guinea pig lungs during constant-flow conditions. Mean pulmonary arterial (Ppa), venous (Pv), and capillary pressures (Pcap, estimated by the double-occlusion method) were measured, and arterial (Ra) and venous resistances (Rv) were calculated. Bolus AA injection (500 micrograms) caused transient increases (peak response 1 min post-AA) in Ppa, Pcap, and Rv without affecting Ra in both Ringer- and blood-perfused lungs. The response was sustained in blood-perfused lungs. AA had no effect on the capillary filtration coefficient in either Ringer- or blood-perfused lungs. AA stimulated the release of thromboxane B2 and 6-ketoprostaglandin F1 alpha in both Ringer- and blood-perfused lungs, but the responses were sustained only in the blood-perfused lungs. Meclofenamate (1.5 X 10(-4) M), a cyclooxygenase inhibitor, abolished the AA-induced pulmonary hemodynamic responses in both Ringer- and blood-perfused lungs, whereas U-60257 (10 microM), a lipoxygenase inhibitor, attenuated the response only in the blood-perfused lungs. In conclusion, AA does not alter pulmonary vascular permeability to water in either Ringer- or blood-perfused lungs. AA mediates pulmonary venoconstriction and thus contributes to the rise in Pcap. The venoconstriction results from the generation of cyclooxygenase-derived metabolites from lung parenchymal cells and blood-formed elements. Lipoxygenase metabolites may also contribute to the vasoconstriction in the blood-perfused lungs. MH - Animal ; Arachidonic Acids/*PHARMACODYNAMICS ; Blood Pressure/DRUG EFFECTS ; Female ; Guinea Pigs ; In Vitro ; Lung ; Meclofenamic Acid/ PHARMACODYNAMICS ; Microcirculation/DRUG EFFECTS ; Osmolar Concentration ; Perfusion ; Prostaglandins X/PHARMACODYNAMICS ; Pulmonary Circulation/ *DRUG EFFECTS ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. ; Thromboxane B2/METABOLISM ; Vascular Resistance/DRUG EFFECTS ; 6-Ketoprostaglandin F1 alpha/METABOLISM SO - J Appl Physiol 1986 Jun;60(6):1972-9 13 UI - 86316786 AU - Allen HR ; Tucker RK ; Geren CR TI - Potentiation of the toxicity of basic peptides from rattlesnake venoms by sodium acetate. AB - The potentiating effect of sodium acetate on the toxicity of crotamine from Crotalus durissus terrificus venom, E toxin from Crotalus horridus horridus venom, and myotoxin a from Crotalus viridus viridis venom was examined. Subcutaneous injection of 6.3 mg/kg body weight of either crotamine or E toxin in 0.6 ml of water or myotoxin a in 0.6 ml of 0.05 M Tris/0.1 M NaCl buffer, pH 9.0, failed to produce lethality in mice. Injection of either E toxin or crotamine at doses of 4.0 mg/kg in 0.6 ml of 20 mM phosphate, pH 7.2, containing 1 M sodium chloride also failed to produce lethality. However, when any of the toxins were injected in 0.4 ml of 1 M sodium acetate, pH 7.0, lethality was observed. LD50 values of 1.43 mg/kg for E toxin, 1.39 mg/kg for crotamine and 0.56 mg/kg for myotoxin a were determined under these conditions. Lethality was also observed when either sodium propionate or sodium butyrate was used as a carrier for E toxin. The effect of these two buffers on crotamine and myotoxin a was not examined. Injection of E toxin s.c. in water followed at various time intervals with i.p. injections of 1 M sodium acetate produced lethality, even when the acetate was injected up to 4 hr after the toxin challenge. MH - Acetic Acids/*TOXICITY ; Animal ; Blood/DRUG EFFECTS ; Crotalid Venoms/ *TOXICITY ; Drug Synergism ; Hydrogen-Ion Concentration ; Mice ; Mice, Inbred C3H ; Support, U.S. Gov't, P.H.S. ; Vehicles/*TOXICITY SO - Toxicon 1986;24(6):553-8 14 UI - 86304380 AU - Yang SY ; Cuebas D ; Schulz H TI - 3-Hydroxyacyl-CoA epimerases of rat liver peroxisomes and Escherichia coli function as auxiliary enzymes in the beta-oxidation of polyunsaturated fatty acids. AB - The beta-oxidation of 2-trans,4-cis-decadienoyl-CoA, an assumed metabolite of linoleic acid, by purified enzymes from mitochondria, peroxisomes, and Escherichia coli was studied. 2-trans,4-cis-Decadienoyl-CoA is an extremely poor substrate of the beta-oxidation system reconstituted from mitochondrial enzymes. The results of a kinetic evaluation lead to the conclusion that in mitochondria 2-trans,4-cis-decadienoyl-CoA is not directly beta-oxidized, but instead is reduced by NADPH-dependent 2,4-dienoyl-CoA reductase prior to its beta-oxidation. Hence, the mitochondrial beta-oxidation of 2-trans,4-cis-decadienoyl-CoA does not require 3-hydroxyacyl-CoA epimerase, a conclusion which agrees with the finding that 3-hydroxyacyl-CoA epimerase is absent from mitochondria (Chu, C.-H., and Schulz, H. (1985) FEBS Lett. 185, 129-134). However, 2-trans,4-cis-decadienoyl-CoA can be slowly oxidized by the bifunctional beta-oxidation enzyme from rat liver peroxisomes, as well as by the fatty acid oxidation complex from E. coli. The observed rates of 2-trans,4-cis-decadienoyl-CoA degradation by these two multi-functional proteins were significantly higher than the values calculated according to steady-state velocity equations derived for coupled enzyme reactions. This is attributed to the direct transfer of L-3-hydroxy-4-cis-decenoyl-CoA from the active site of enoyl-CoA hydratase to that of 3-hydroxyacyl-CoA dehydrogenase on the same protein molecule. All observations together lead to the suggestion that the chain shortening of 2-trans,4-cis-decadienoyl-CoA in peroxisomes and in E. coli occurs simultaneously by two different pathways. The major pathway involves the NADPH-dependent 2,4-dienoyl-CoA reductase, whereas 3-hydroxyacyl-CoA epimerase functions in the metabolism of D-3-hydroxyoctanoyl-CoA which is formed via the minor pathway. MH - Animal ; Cattle ; Epimerases/*METABOLISM ; Escherichia Coli/*ENZYMOLOGY ; Fatty Acids, Unsaturated/*METABOLISM ; Isomerases/*METABOLISM ; Kinetics ; Liver/*ULTRASTRUCTURE ; Microbodies/*ENZYMOLOGY ; Mitochondria/ ENZYMOLOGY ; Models, Chemical ; Oxidation-Reduction ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. SO - J Biol Chem 1986 Sep 15;261(26):12238-43 15 UI - 86299694 AU - Chu TC ; Candia OA ; Iizuka S TI - Effects of forskolin, prostaglandin F2 alpha, and Ba2+ on the short-circuit current of the isolated rabbit iris-ciliary body. AB - To gain information on the role of cyclic AMP (cAMP), ion transport and cell membrane permeability on aqueous humor formation, agents with well-known effects on transport properties in other epithelia were tested on the isolated rabbit iris-ciliary body. Forskolin stimulated the short-circuit current (SCC) by 37.5% when added to the aqueous-side solution. Forskolin was ineffective when added to the blood-side solution or when HCO3- was absent from the bathing solutions. The effect of forskolin confirms the presence of adenylate cyclase in the ciliary epithelium and the involvement of cAMP in ion transport. In HCO3- -rich media, 5 X 10(-5) M prostaglandin F2 alpha (PGF2 alpha), produced a prompt 25% increase in the SCC when added to the aqueous-side, and a small stimulatory SCC response when added to the blood-side. No change in SCC occurred when PGF2 alpha was added to either side of a HCO3- -free bathing solution. It is implied that cAMP acts on a HCO3- dependent transport system. These results are consistent with the previously observed stimulation of the SCC by 8Br-cAMP. BaCl2, 2.5 mM, on the aqueous-side increased the SCC by 240.5%, but reduced the SCC by 26% when added to the blood-side solution. The Ba2+ effects indicate the presence of high conductance K+ channels in the basolateral membranes of both the pigmented and non-pigmented cell layers. MH - Animal ; Barium/*PHARMACODYNAMICS ; Ciliary Body/*PHYSIOLOGY ; Electric Conductivity ; Electrophysiology ; Female ; Forskolin/*PHARMACODYNAMICS ; In Vitro ; Intraocular Pressure/DRUG EFFECTS ; Iris/*PHYSIOLOGY ; Prostaglandins F/*PHARMACODYNAMICS ; Rabbits ; Support, U.S. Gov't, P.H.S. SO - Curr Eye Res 1986 Jul;5(7):511-6 16 UI - 86260753 AU - Younger EW ; Szabo RM TI - The stability of prostaglandin E1 in dilute physiological solutions at 37 degrees C. AB - The stability of prostaglandin E1 (PGE1) in three physiologic solutions was studied at body temperature (37 degrees C) over 32 days. The solutions were 100 mcg/ml PGE1 in isotonic saline (pH 4.5), 0.1 M phosphate buffered water (pH 7.4) or 0.01 M phosphate buffered isotonic saline (pH 4.7). PGE1 was found to be more stable in the saline and buffered saline solutions at the pH values of 4.5 and 4.7 respectively. Twenty-five per cent of the PGE1 remained at 32 days in these solutions while 95% of the PGE1 in the solution at pH 7.4 was degraded by day 14. The degradation of PGE1 in the acidic solutions appeared to be nearly linear when plotted on a semilog graph. This data allows one to use PGE1 in an aqueous, slightly acidic solution in a system that requires it to be kept at 37 degrees C for up to 30 days such as a biologically implantable pump. Investigators can use such a system in vivo to study the effect of known concentrations of PGE1 given over a period of time to a specific area of interest. MH - *Alprostadil/ADMINISTRATION & DOSAGE ; Drug Stability ; Hydrogen-Ion Concentration ; Solutions ; Temperature ; Time Factors SO - Prostaglandins 1986 May;31(5):923-7 17 UI - 86243274 AU - Cistola DP ; Atkinson D ; Hamilton JA ; Small DM TI - Phase behavior and bilayer properties of fatty acids: hydrated 1:1 acid-soaps. AB - The physical properties in water of a series of 1:1 acid-soap compounds formed from fatty acids and potassium soaps with saturated (10-18 carbons) and omega-9 monounsaturated (18 carbons) hydrocarbon chains have been studied by using differential scanning calorimetry (DSC), X-ray diffraction, and direct and polarized light microscopy. DSC showed three phase transitions corresponding to the melting of crystalline water, the melting of crystalline lipid hydrocarbon chains, and the decomposition of the 1:1 acid-soap compound into its parent fatty acid and soap. Low- and wide-angle X-ray diffraction patterns revealed spacings that corresponded (with increasing hydration) to acid-soap crystals, hexagonal type II liquid crystals, and lamellar liquid crystals. The lamellar phase swelled from bilayer repeat distances of 68 (at 45% H2O) to 303 A (at 90% H2O). Direct and polarized light micrographs demonstrated the formation of myelin figures as well as birefringent optical textures corresponding to hexagonal and lamellar mesophases. Assuming that 1:1 potassium hydrogen dioleate and water were two components, we constructed a temperature-composition phase diagram. Interpretation of the data using the Gibbs phase rule showed that, at greater than 30% water, hydrocarbon chain melting was accompanied by decomposition of the 1:1 acid-soap compound and the system changed from a two-component to a three-component system. Comparison of hydrated 1:1 fatty acid/soap systems with hydrated soap systems suggests that the reduced degree of charge repulsion between polar groups causes half-ionized fatty acids in excess water to form bilayers rather than micelles.(ABSTRACT TRUNCATED AT 250 WORDS) MH - Calorimetry, Differential Scanning ; Comparative Study ; *Fatty Acids ; *Lipid Bilayers ; Micelles ; Molecular Conformation ; *Soaps ; Structure-Activity Relationship ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. ; *Surface-Active Agents ; X-Ray Diffraction SO - Biochemistry 1986 May 20;25(10):2804-12 18 UI - 86242252 AU - Meadows J ; Smith RC ; Reeves J TI - Uric acid protects membranes and linolenic acid from ozone-induced oxidation. AB - Aqueous preparations of linolenic acid, bovine serum albumin, and bovine erythrocyte membrane fragments were bubbled with ozone in the presence or absence of uric acid. Ozonation of the membrane fragments or the bovine serum albumin did not result in protein degradation. After 15 min of ozonation, the absorbance of the thiobarbituric acid-reactive material increased by 0.34 in the linolenic acid preparation and by 0.08 in the suspension of membrane fragments. In the presence of uric acid, these changes in absorbance were reduced to 0.14 for the fatty acid and to 0.01 for the membrane fragments. This result indicates that uric acid protects lipids from ozone-induced oxidation. MH - Animal ; Cattle ; Cell-Free System ; Erythrocyte Membrane/*DRUG EFFECTS ; Free Radicals ; Linolenic Acids/*METABOLISM ; Membrane Lipids/METABOLISM ; Oxidation-Reduction ; *Ozone ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, Non-P.H.S. ; Uric Acid/*PHARMACODYNAMICS SO - Biochem Biophys Res Commun 1986 May 29;137(1):536-41 19 UI - 86236444 AU - Merker MP ; Levine L TI - A protein from the marine mollusc Aplysia californica that is hemolytic and stimulates arachidonic acid metabolism in cultured mammalian cells. AB - Aqueous extracts of the foot muscle of the marine mollusc Aplysia californica contain a proteins(s) that stimulates cytolysis and prostaglandin production in the C-9 rat liver cell line and hemolysis of red blood cells. Partial purification of the protein by ion exchange chromatography and fast protein liquid chromatography resulted in parallel increases in specific activity for prostaglandin production and hemolysis. Prostaglandin release occurred both at cytolytic concentrations of the protein and at lower concentrations that caused no apparent alterations in cell morphology. Differential sensitivity of a variety of cell lines to stimulation of prostaglandin production was observed; one group of cells, including the C-9 rat liver cell line, displayed a 5-fold stimulation of arachidonic acid metabolism with 1-3 micrograms of a partially purified protein preparation, while a second group was insensitive to concentrations as high as 20 micrograms protein of that preparation. Red blood cells also displayed differential sensitivity to hemolysis: rhesus and squirrel monkey red blood cells were 100-fold more sensitive to lysis by the protein than cebus monkey erythrocytes. Both activities were abolished by treatment with pepsin, trypsin or heat and both had a molecular weight of congruent to 45,000, as determined by gel filtration. Stimulation of both prostaglandin synthesis and hemolysis was Ca2+ dependent. These observations suggest, but do not prove, that the protein that causes lysis of red blood cells and the protein that stimulates arachidonic acid metabolism in the C-9 cell line is the same. MH - Animal ; Aplysia/*METABOLISM ; Arachidonic Acids/METABOLISM ; Cebus ; Chromatography, High Pressure Liquid ; Electrophoresis, Polyacrylamide Gel ; Heat ; Hemolysis/DRUG EFFECTS ; In Vitro ; Liver/METABOLISM ; Lyngbya Toxins/*ISOLATION & PURIFICATION/PHARMACODYNAMICS ; Macaca mulatta ; Mice ; Molecular Weight ; Muscles/ANALYSIS ; Prostaglandins/ *BIOSYNTHESIS ; Rabbits ; Rats ; Saimiri ; Species Specificity ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. SO - Toxicon 1986;24(5):451-65 20 UI - 86218591 AU - Suzuki Y ; Orii T ; Mori M ; Tatibana M ; Hashimoto T TI - Deficient activities and proteins of peroxisomal beta-oxidation enzymes in infants with Zellweger syndrome. AB - The activities and amounts of enzyme proteins of peroxisomal beta-oxidation in Japanese children with Zellweger syndrome were investigated. Cyanide-insensitive fatty acid oxidation, peroxisomal enoyl-CoA hydratase and 3-oxoacyl-CoA thiolase activities were not detectable in liver tissue at autopsy, whereas the activities of mitochondrial enoyl-CoA hydratase, 3-oxoacyl-CoA thiolase and carnitine palmitoyltransferase were similar to those in the healthy controls. On immunoblot analysis, immunoreactive proteins of peroxisomal acyl-CoA oxidase, bifunctional protein and 3-oxoacyl-CoA thiolase were not detected in the livers, kidneys and fibroblasts from the patients. Proteins of catalase and some enzymes of mitochondrial fatty acid oxidation were similar as in normal controls. These data indicate that increased levels of very-long-chain fatty acids in Zellweger syndrome are due to the lack of the enzyme proteins of peroxisomal beta-oxidation. MH - Acetyl CoA Acyltransferase/*DEFICIENCY ; Acyltransferases/*DEFICIENCY ; Brain Diseases/ENZYMOLOGY ; Electrophoresis, Polyacrylamide Gel ; Enoyl CoA Hydratases/*DEFICIENCY ; Fatty Acids/*METABOLISM ; Female ; Human ; Hydro-Lyases/*DEFICIENCY ; Immunologic Technics ; Infant ; Kidney Diseases/ENZYMOLOGY ; Liver/ENZYMOLOGY ; Liver Diseases/ENZYMOLOGY ; Male ; Microbodies/*ENZYMOLOGY ; Oxidation-Reduction ; Oxidoreductases/ *DEFICIENCY ; Syndrome SO - Clin Chim Acta 1986 Apr 30;156(2):191-6 21 UI - 86216121 AU - Noy N ; Donnelly TM ; Zakim D TI - Physical-chemical model for the entry of water-insoluble compounds into cells. Studies of fatty acid uptake by the liver. AB - The spontaneous transfer of water-insoluble substances from plasma to the interior of cells would involve a series of steps in which the substance of interest dissociates from albumin in plasma, enters the outer half of the plasma membrane of a cell, crosses the bilayer, and then dissociates from the inner half of the plasma membrane to enter cell cytosol and diffuses to sites of its metabolism. We have examined the behavior of long-chain fatty acids in the uptake process, assuming that none of these steps is facilitated by the cell during the entry of fatty acids into the liver. Comparison of the spontaneous rates for each individual step with rates of uptake of fatty acid by perfused liver leads to the conclusion that the uptake of fatty acids is not limited by kinetic factors but is determined instead by the equilibrium distribution (Keq) of fatty acids between albumin in plasma and the phospholipids of the plasma membrane. This idea was examined further by determining whether there was a relationship between the value for Keq and rates of uptake of a fatty acid and the pattern of kinetics for uptake. The data indicate that there is a linear relationship between Keq and the rate of uptake, that uptake rates can be predicted with a high degree of accuracy from thermodynamic data, and that the pattern of kinetics of uptake is compatible with the idea that the uptake rate is determined by the relative affinity of a fatty acid for albumin and membranes. MH - Animal ; Biological Transport ; Cytosol/METABOLISM ; Fatty Acids, Nonesterified/*METABOLISM ; Liver/*METABOLISM ; Male ; Mathematics ; Models, Biological ; Myristic Acids/METABOLISM ; Palmitic Acids/ METABOLISM ; Perfusion ; Rats ; Rats, Inbred Strains ; Solubility ; Support, U.S. Gov't, P.H.S. ; Water SO - Biochemistry 1986 Apr 22;25(8):2013-21 22 UI - 86216079 AU - Storch J ; Kleinfeld AM TI - Transfer of long-chain fluorescent free fatty acids between unilamellar vesicles. AB - Movement of free fatty acids (ffa) between small unilamellar vesicles (SUV) was studied by measuring the transfer of fluorescent n-(9-anthroyloxy)-labeled analogues (AOffa) between donor and acceptor vesicles. Donors were composed of egg phosphatidylcholine (PC) loaded with 1-2 mol % AOffa, and acceptors were egg PC containing 10-12 mol % N-(7-nitro-2,1,3-benzoxadiazol-4-yl)phosphatidylethanolamine (NBD-PE). The fluorescence of AO added directly to acceptor SUV was greater than 98% quenched by energy transfer to NBD. Thus, AOffa movement from donor to acceptor was monitored by the time-dependent decrease in AO fluorescence. The transfer of the short-chain AOffa, although too fast to be resolved by the methods used here, is consistent with studies that find transfer rates on the order of milliseconds and kinetics which are first order. In contrast, transfer rates for the long-chain AOffa are more than 2 orders of magnitude slower, and the kinetics of the transfer process are best described by the sum of two exponentials plus a constant. The ffa ionization state was also found to be an important determinant of transfer rate. The charged species transferred an average of 10-fold faster than the protonated ffa. The ffa pKa in the membrane is 9, as calculated from the pH dependence of transfer. Similar to results found for other lipids, long-chain AOffa are transferred via water rather than a collision-mediated process. The aqueous phase route of AOffa intermembrane transfer is indicated by the lack of effect on transfer of large alterations in the product of donor and acceptor phospholipid concentrations. Moreover, the transfer rate is decreased as [NaCl] is increased from 0.1 to 4 M. This effect of ionic strength is probably due not only to a decrease in the aqueous phase partition of the AOffa but also to an alteration in bilayer structure, as measured by fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene. The observed kinetics are consistent with a model in which the transfer involves two steps: transbilayer movement between the inner and outer bilayer leaflets, followed by transfer from the outer leaflet to the aqueous phase (off rate). Within the framework of this model, the observed slow rate is primarily determined by the rate of transbilayer movement, and the observed fast rate is approximately equal to the off rate. The off rate is about 10-fold faster than the rate of transbilayer movement. MH - Comparative Study ; *Fatty Acids, Nonesterified ; Fluoresceins ; Fluorescent Dyes ; Hydrogen-Ion Concentration ; Kinetics ; *Liposomes ; Mathematics ; Models, Biological ; Osmolar Concentration ; *Phosphatidylcholines ; Spectrometry, Fluorescence ; Structure-Activity Relationship ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, Non-P.H.S. SO - Biochemistry 1986 Apr 8;25(7):1717-26 23 UI - 86212652 AU - Sato M ; Dunn MJ TI - Osmolality, vasopressin-stimulated cAMP, and PGE2 synthesis in rat collecting tubule cells. AB - Using rat renal papillary collecting tubule (RPCT) cells in culture, we examined the interactions of extracellular osmolality, vasopressin-stimulated cAMP, and prostaglandin E2 (PGE2) synthesis. Hypertonic solutions composed of equiosmolar amounts of urea and sodium chloride, 900-2,400 mosM, potentiated the increases of intracellular cAMP after vasopressin stimulation. Sodium chloride, rather than urea, was the important solute. The mechanism of this augmented cAMP response was complex, probably involving increased synthesis, decreased degradation, and reduced efflux of cAMP from the RPCT cells. The potentiating actions of hypertonic sodium chloride were specific for vasopressin-stimulated cAMP and were not observed for forskolin or PGE2-stimulated cAMP. Hypertonic solutions inhibited RPCT cell PGE2 production, and sodium chloride, rather than urea, was again the important solute. The enzymatic site of sodium chloride inhibition of PGE2 synthesis was apparently on the phospholipase enzymes, assessed by calcium ionophore and bradykinin stimulation, and not on cyclooxygenase, measured by arachidonic acid responsiveness. Reductions of osmolality, from 1,800 to 300 mosM, acutely increased PGE2 release, possibly through a calcium-dependent stimulation of phospholipase. We conclude that conditions that prevail in vivo during antidiuresis, namely hypertonicity of the papillary interstitium, may augment vasopressin responsiveness through increments of collecting tubule cAMP and reductions of PGE2 which could, in concert, maximize water reabsorption in the collecting tubule. MH - A-23187/PHARMACODYNAMICS ; Adenosine Cyclic Monophosphate/*BIOSYNTHESIS ; Adenyl Cyclase/METABOLISM ; Animal ; Arachidonic Acids/PHARMACODYNAMICS ; Argipressin/*PHARMACODYNAMICS ; Forskolin/PHARMACODYNAMICS ; Kidney Tubules/*METABOLISM ; Kidney Tubules, Collecting/CYTOLOGY/ENZYMOLOGY/ *METABOLISM ; Osmolar Concentration ; Phosphodiesterase Inhibitors/ PHARMACODYNAMICS ; Prostaglandins E/*BIOSYNTHESIS/PHARMACODYNAMICS ; Rats ; Rats, Inbred Strains ; Sodium Chloride/PHARMACODYNAMICS ; Stimulation, Chemical ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. ; Urea/ PHARMACODYNAMICS ; 1-Methyl-3-Isobutylxanthine/PHARMACODYNAMICS SO - Am J Physiol 1986 May;250(5 Pt 2):F802-10 24 UI - 86211288 AU - Bojesen E ; Bojesen IN TI - The influence of renal papillary urea concentrations and of plasma vasopressin on the urinary prostaglandins E2 and F2 alpha excretion in conscious rats in steady state of urine formation. AB - Urinary excretion rates of PGE2 and PGF2 alpha were measured radioimmunologically in four different groups of unanaesthetized rats: water diuretic rats (I), rats with free access to water (II), water deprived rats (III) and 1.5% saline-loaded rats (IV). The animals were decapitated when steady states of urine formation were ascertained for three to six spontaneously delivered urine portions. Plasma vasopressin was measured radioimmunologically and urea, sodium, potassium concentrations and osmolalities of papillary fluids and of bladder urines were determined. Group means of urinary prostaglandin excretion, papillary urea concentration and logarithmic-transformed plasma vasopressin values vary in parallel for three of the groups (I, II and III) but a dissociation of the effects of papillary urea and vasopressin on the prostaglandin excretion was obtained for group IV. Statistical analyses indicated that the differences in prostaglandin excretion rates between group I and the three other groups are accounted for by the combined effects of vasopressin and papillary urea. The results support the hypothesis that vasopressin stimulates release of arachidonic acid in the papilla and that urea inhibits the trapping of this prostaglandin precursor in cellular lipids. The ratio of urinary PGF2 alpha to PGE2 varied greatly between groups but no consistent dependency on the measured parameters was found. MH - Animal ; Diuresis/DRUG EFFECTS ; Kidney Medulla/*ANALYSIS ; Osmolar Concentration ; Potassium/ANALYSIS ; Prostaglandins E/*URINE ; Prostaglandins F/*URINE ; Rats ; Rats, Inbred Strains ; Sodium/ANALYSIS ; Sodium Chloride/PHARMACODYNAMICS ; Urea/*ANALYSIS ; Urine ; Vasopressins/ *BLOOD SO - Acta Physiol Scand 1986 Feb;126(2):279-88 25 UI - 86187861 AU - Blatt E ; Corin AF TI - The microsecond rotational motions of eosin-labelled fatty acids in multilamellar vesicles. AB - The rotational properties of two eosin-labelled fatty acids of different alkyl chain length have been studied in large multilamellar dimyristoylphosphatidylcholine vesicles. The location of the probes at the surface region were ascertained by quenching experiments using a hydrophilic divalent cation solubilized in the aqueous phase (Cu2+) and a hydrophobic aromatic aniline (N,N-dimethylaniline) associated with the lipid. Phosphorescence anisotropy measurements reveal that above the phospholipid phase transition the polarization of eosin luminescence decays monoexponentially in the micro-to-millisecond time range, while below the phase transition a biexponential decay is observed. A model is proposed which attributes the time constants to two separate motions, discrete jumps or 'flipping' of the eosin moiety within restricted boundaries and long-axis rotation. The value of the time-independent term changes with probe position and temperature and reflects orientational constraints imposed by lipid-chromophore interactions. The implications of these results for the study of protein rotations in membranes are discussed. MH - Comparative Study ; Dimyristoylphosphatidylcholine ; *Eosin ; *Fatty Acids, Nonesterified ; *Liposomes ; Luminescence ; Models, Biological ; Structure-Activity Relationship ; Support, Non-U.S. Gov't ; Thermodynamics SO - Biochim Biophys Acta 1986 May 9;857(1):85-94 26 UI - 86184158 AU - Hollander D ; Gerard EM ; Boyd CA TI - Transport of butyric acid in vascularly perfused anuran small intestine: importance of pH and anion transport. AB - Butyric acid transport was studied in the isolated, vascularly perfused frog small intestine. At luminal butyric acid concentrations of 5-50 mM, absorption was a nonlinear function of the luminal concentration, whereas the relationship of absorption to concentration remained linear at 0-1,000 microM. The most important factor regulating the rate and direction of butyric acid transport was the pH. We used unidirectional flux analysis to determine net transport across the epithelium while the pH of the luminal or vascular compartments was changed. We found a four- to fivefold decrease in butyric acid transport into the portal circulation as the lumen pH was increased from 6.0 to 8.0. The pH of the vascular perfusate influenced the vascular-to-lumen transport of butyric acid in the same proportions. The second important regulatory factor of butyric acid transport was the 4,4'-diisothiocyananostilbene-2,2'-disulfonic acid (DIDS)-sensitive anion transport protein. DIDS added to the lumen at 10(-6) M decreased butyric acid transport by approximately 40% at pH 7.4. DIDS also inhibited butyric acid transport when added to the vascular perfusate or when transport was measured in a vascular-to-lumen direction. We suggest that, at the relatively low pH of the proximal small intestine, butyric acid becomes protonated and lipophilic and is mainly transported directly through the cell membrane. At the more alkaline pH of the distal small intestine butyric acid is in the ionized form and transport by the DIDS-sensitive anion transport protein may predominate. MH - Acetazolamide/PHARMACODYNAMICS ; Amiloride/PHARMACODYNAMICS ; Animal ; Anions/*METABOLISM ; Biological Transport ; Butyrates/*METABOLISM ; Butyric Acids/*METABOLISM ; *Hydrogen-Ion Concentration ; Intestine, Small/*METABOLISM ; Kinetics ; Methylglucosides/METABOLISM ; Perfusion ; Probenecid/PHARMACODYNAMICS ; Rana Esculenta ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. ; SITS/ANALOGS & DERIVATIVES/PHARMACODYNAMICS SO - Am J Physiol 1986 Apr;250(4 Pt 1):G469-74 27 UI - 86178050 AU - Kasser TR ; Martin RJ TI - Induction of ventrolateral hypothalamic fatty acid oxidation in diabetic rats. AB - Diabetic rats were used to test a previous hypothesis that alterations in ventrolateral hypothalamic (VLH) fatty acid oxidation observed in over- and underfed rats were a function of the animals' peripheral energy balance and not merely a function of their energy intake. Standard adaptations to the diabetic condition were exhibited in streptozotocin diabetic rats such as depressed body weights, hyperphagia and hyperglycemia, elevated serum free fatty acids, depressed insulin concentrations, depressed hepatic glucose oxidation and elevated hepatic fatty acid oxidation. Rates of VLH fatty acid oxidation to CO2 and to an acid, water-soluble fraction in diabetic rats were elevated relative to non-diabetic rats. The alterations in VLH fatty acid oxidation in diabetic rats were similar to changes previously observed in animals exhibiting a negative energy balance. The results were discussed with respect to the concept that VLH fatty acid oxidation was a component in the recognition of peripheral energy balance and, in part, served to alter the regulators of energy balance and food intake. MH - Animal ; Diabetes Mellitus, Experimental/*METABOLISM ; Eating ; Energy Metabolism ; Hypothalamic Area, Lateral/*METABOLISM ; Hypothalamus, Middle/METABOLISM ; Liver/METABOLISM ; Male ; Oxidation-Reduction ; Palmitates/*METABOLISM ; Palmitic Acids/*METABOLISM ; Rats ; Rats, Zucker ; Streptozotocin SO - Physiol Behav 1986;36(2):385-8 28 UI - 86162769 AU - Haylor J ; Lote CJ ; Thewles A TI - The effect of sodium bicarbonate on the flow-dependency of urinary prostaglandin excretion in man. AB - The influence of oral water loading on the excretion rate of prostaglandin (PG) E was investigated in healthy human subjects in a control study where the urine was acidic (pH 5.7) and after oral sodium bicarbonate, which made the urine mildly alkaline (pH 7.2). PGE was immediately extracted from urine and measured by a radioimmunoassay technique. After sodium bicarbonate (5 g) the urinary PGE excretion rate was some three-fold higher (P less than 0.01) than in the control study, in the absence of any significant difference in the urine flow (approximately 80 ml/h). In the control study (urine pH 5.7) the urinary PGE excretion rate increased significantly (P less than 0.01) as the urine flow rose in response to the oral fluid load. However, after sodium bicarbonate, PGE excretion did not alter after the fluid load despite a 10-fold increase in urine flow. Since after bicarbonate administration PGE excretion is independent of urine flow, mildly alkaline urine may represent a condition under which renal PGE synthesis can be effectively assessed from measurements of urinary PGE excretion, in the presence of changes in urine flow. In addition, the results are compatible with the hypothesis that, in man, PGE may be passively reabsorbed in the distal nephron, and a reduction in this reabsorption could contribute to or be responsible for the dependency of the excretion rate of PGE on urine flow. MH - Adult ; Bicarbonates/*PHARMACODYNAMICS ; *Diuresis ; Human ; Hydrogen-Ion Concentration ; Male ; Osmolar Concentration ; Prostaglandins E/*URINE ; Sodium/*PHARMACODYNAMICS SO - Clin Sci 1986 Feb;70(2):141-5 29 UI - 86160591 AU - Berry CN ; Griffiths RJ ; Hoult JR ; Moore PK ; Taylor GW TI - Identification of 6-oxo-prostaglandin E1 as a naturally occurring prostanoid generated by rat lung. AB - The spontaneous release of prostanoids from rat isolated perfused lungs was studied after acid/organic extraction of perfusates by bioassay, radioimmunoassay, thin layer and high performance liquid chromatographic methods and by gas chromatography-negative ion mass spectroscopy (g.c.n.i.m.s.). An acid/organic extractable anti-aggregatory vasodilator prostaglandin which inhibited the twitch response of the field-stimulated guinea-pig vas deferens was released from the Krebs-perfused rat lung in nanogram amounts similar to those of other detected prostanoids. Parallel biological assay suggested that this prostaglandin had very closely similar pharmacological activity to authentic 6-oxo-prostaglandin E1 (6-oxo-PGE1), a metabolite of prostacyclin (PGI2) generated by the action of the enzyme 9-hydroxyprostaglandin dehydrogenase (9-PGDH). 6-oxo-PGE1 was identified conclusively in extracts of rat lung perfusate by thin layer chromatography, high performance liquid chromatography and g.c./m.s. combined with bioassay (inhibition of platelet aggregation), and its covalent structure was defined by g.c. negative ion chemical ionization mass spectroscopy. The rank order of spontaneous release of prostanoids (measured by radioimmunoassay) from the perfused rat lung was 6-oxo-PGF1 alpha greater than thromboxane B2 (TXB2) greater than PGE2 greater than 6-oxo-PGE1 (measured biologically) greater than PGF2 alpha. Release of all five prostanoids was inhibited by indomethacin, but only that of 6-oxo-PGE1 was inhibited by naringenin. Rat lung 100,000 g cytosolic supernatants contained 9-PGDH activity capable of removing 9 beta-tritium from labelled prostacyclin and forming an acid/organic extractable 6-oxo-PGE1-like anti-aggregatory substance. This 9-PGDH activity was inhibited by naringenin (IC50 10.3 microM).(ABSTRACT TRUNCATED AT 250 WORDS) MH - Alprostadil/*ANALOGS & DERIVATIVES/ANALYSIS/BIOSYNTHESIS ; Animal ; Chromatography, High Pressure Liquid ; Chromatography, Thin Layer ; Cytosol/ENZYMOLOGY ; Flavones/PHARMACODYNAMICS ; Hydrogen-Ion Concentration ; Hydroxyprostaglandin Dehydrogenases/ANTAGONISTS & INHIBITORS/METABOLISM ; In Vitro ; Lung/ENZYMOLOGY/*METABOLISM ; Male ; Mass Fragmentography ; Perfusion ; Prostaglandins/ANALYSIS/*BIOSYNTHESIS ; Radioimmunoassay ; Rats ; Rats, Inbred Strains ; Support, Non-U.S. Gov't SO - Br J Pharmacol 1986 Feb;87(2):327-35 30 UI - 86094356 AU - Hamilton JA ; Cistola DP TI - Transfer of oleic acid between albumin and phospholipid vesicles. AB - The net transfer of oleic acid between egg phosphatidylcholine unilamellar vesicles and bovine serum albumin has been monitored by 13C NMR spectroscopy and 90% isotopically substituted [1-13C]oleic acid. The carboxyl chemical shifts of oleic acid bound to albumin were different from those for oleic acid in phospholipid vesicles. Therefore, in mixtures of donor particles (vesicles or albumin with oleic acid) and acceptor particles (fatty acid-free albumin or vesicles), the equilibrium distribution of oleic acid was determined from chemical shift and peak intensity data without separation of donor and acceptor particles. In a system containing equal masses of albumin and phospholipid and a stoichiometry of 4-5 mol of oleic acid per mol of albumin, the oleic acid distribution was pH dependent, with greater than or equal to 80% of the oleic acid associated with albumin at pH 7.4; association was greater than or equal to 90% at pH 8.0. Decreasing the pH below 7.4 markedly decreased the proportion of fatty acid bound to albumin; at pH 5.4, less than or equal to 10% of the oleic acid was bound to albumin and greater than 90% was associated with vesicles. The distribution was reversible with pH and was independent of whether vesicles or albumin acted as a donor. These data suggest that pH may strongly influence the partitioning of fatty acid between cellular membranes and albumin. The 13C NMR method is also advantageous because it provides information about the structural environments of oleic acid bound to albumin or phospholipid, the ionization state of oleic acid in each environment, and the structural integrity of the vesicles. In addition, minimum and maximum limits for the exchange rates of oleic acid among different environments were obtained from the NMR data. MH - Fatty Acids/METABOLISM ; Hydrogen-Ion Concentration ; Liposomes/ *METABOLISM ; Nuclear Magnetic Resonance ; Oleic Acids/*METABOLISM ; Phosphatidylcholines/*METABOLISM ; Serum Albumin, Bovine/*METABOLISM ; Support, U.S. Gov't, P.H.S. SO - Proc Natl Acad Sci USA 1986 Jan;83(1):82-6