Apparent Inhibition of the Plasma Membrane Ca2+ Pump by Oleic Acid

Rw, Pine; Vincenzi, Frank F.; Cj, Carrico

doi:10.1097/00005373-198305000-00002

Cited by 9 publications

(3 citation statements)

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“…In a concentration-dependent fashion, oleate activated or inhibited the Ca2+-transport ATPase of membranes isolated from human red cells [31]. At concentrations up to 50 pmol 1-', oleate increased the activity of the Ca2+-transport ATPase rather selectively (opposite to Na+-and K+-dependent ATPase and Mg2+-dependent ATPase), but at higher concentrations oleate inhibited ATPase activities [31].…”

Section: Discussionmentioning

confidence: 99%

Effect of modulators on prostasome membrane‐bound ATPase in human seminal plasma

Ronquist

1987

Eur J Clin Investigation

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The Mg2+- and Ca2+-dependent ATPase system in human seminal fluid is linked to membranes encasing small organelles denoted 'prostasomes'. This activity was completely pelleted after ultracentrifugation at 105,000 X g, provided the seminal plasma was diluted 1:10. On the contrary, prostatic acid phosphatase activity remained in the supernatant and was inhibited to about 75% by tartrate (0.5 mmol l-1) contrasting with the ATPase system that was not inhibited. Calmodulin, in the concentration interval 0.30-0.90 mumol l-1, did not further activate the ATPase system. Calmidazolium, which is a highly lipophilic substance, was a competitive inhibitor of the Mg2+- and Ca2+-dependent ATPase and half maximal inhibition was attained at 2-3 mumol l-1 calmidazolium. This inhibition was antagonized to a moderate degree (25%, P less than 0.02) by calmodulin, 0.60 mumol l-1. Quercetin, at concentrations of 30-60 mumol l-1, did not influence the prostasome membrane ATPase in any direction. Oleate was an inhibitor of the ATPase system at any concentration up to 50 mumol l-1. This inhibition was not counteracted to an appreciable extent by calmodulin. These results displayed a pattern giving support to the view that the Mg2+- and Ca2+-dependent ATPase of the prostasome membrane may be the molecular basis for vectorial transport of Ca2+ into prostasomes.

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Section: Discussionmentioning

confidence: 99%

Effect of modulators on prostasome membrane‐bound ATPase in human seminal plasma

Ronquist

1987

Eur J Clin Investigation

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“…The oleic acid induced lung injury is probably primarily caused by a direct toxic effect on the endothelial wall [29,30]. A mechanism might be the potency of oleic acid to inhibit the activity of the Ca-pump and the (Na + + K +)-ATPase [31,32], leading to dysfunction of the cell membrane. Electronic microscopical investigation in a previous study [20] revealed signs of degeneration of the endothelium, like swelling and vacuolization.…”

Section: Mechanisms Of Injurymentioning

confidence: 99%

A stable model of respiratory distress by small injections of oleic acid in pigs

et al. 1996

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“…The activity of human' red cell membrane Ca2l-ATPase is regulated by several factors, including membrane phospholipid and fatty acid content (Niggli et al, 1981;Sarkadi et al, 1982). Unsaturated fatty acids, such as oleic and linoleic acids, have been shown in vitro to enhance the activity of Ca2+-ATPase in purified enzyme preparations (Niggli et al, 1981) and in membrane enzyme models (Pine et al, 1983;Wetzker et al, 1983). Thyroid hormone analogues are hydrophobic molecules that have specific (Botta & Farias, 1985) and nonspecific (Davis et al, 1984) interactions with cell membranes.…”

Section: Introductionmentioning

confidence: 99%

Action of long-chain fatty acids in vitro on Ca2+-stimulatable, Mg2+-dependent ATPase activity in human red cell membranes

Davis

Blas

et al. 1987

Biochemical Journal

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Human red cell membrane Ca2+-stimulatable, Mg2+-dependent adenosine triphosphatase (Ca2+-ATPase) activity and its response to thyroid hormone have been studied following exposure of membranes in vitro to specific long-chain fatty acids. Basal enzyme activity (no added thyroid hormone) was significantly decreased by additions of 10(-9)-10(-4) M-stearic (18:0) and oleic (18:1 cis-9) acids. Methyl oleate and elaidic (18:1 trans-9), palmitic (16:0) and lauric (12:0) acids at 10(-6) and 10(-4) M were not inhibitory, nor were arachidonic (20:4) and linolenic (18:3) acids. Myristic acid (14:0) was inhibitory only at 10(-4) M. Thus, chain length of 18 carbon atoms and anionic charge were the principal determinants of inhibitory activity. Introduction of a cis-9 double bond (oleic acid) did not alter the inhibitory activity of the 18-carbon moiety (stearic acid), but the trans-9 elaidic acid did not cause enzyme inhibition. While the predominant effect of fatty acids on erythrocyte Ca2+-ATPase in situ is inhibition of basal activity, elaidic, linoleic (18:2) and palmitoleic (16:1) acids at 10(-6) and 10(-4) M stimulated the enzyme. Methyl elaidate was not stimulatory. These structure-activity relationships differ from those described for fatty acids and purified red cell Ca2+-ATPase reconstituted in liposomes. Thyroid hormone stimulation of Ca2+-ATPase was significantly decreased by stearic and oleic acids (10(-9)-10(-4) M), but also by elaidic, linoleic, palmitoleic and myristic acids. Arachidonic, palmitic and lauric acids were ineffective, as were the methyl esters of oleic and elaidic acids. Thus, inhibition of the iodothyronine effect on Ca2+-ATPase by fatty acids has similar, but not identical, structure-activity relationships to those for basal enzyme activity. To examine mechanisms for these fatty acid effects, we studied the action of oleic and stearic acids on responsiveness of the enzyme to purified calmodulin, the Ca2+-binding activator protein for Ca2+-ATPase. Oleic and stearic acids (10(-9)-10(-4) M) progressively inhibited, but did not abolish, enzyme stimulation by calmodulin (10(-9) M). Double-reciprocal analysis of the effect of oleic acid on calmodulin stimulation indicated noncompetitive inhibition. Addition of calmodulin to membranes in the presence of equimolar oleic acid restored basal enzyme activity. Oleic acid also reduced 125I-calmodulin binding to membranes, but had no effect on the binding of [125I]T4 by ghosts. The mechanism of the decrease by long chain fatty acids of Ca2+-ATPase activity in situ in human red cell ghosts thus is calmodulin-dependent and involves reduction in membrane binding of calmodulin.

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Apparent Inhibition of the Plasma Membrane Ca2+ Pump by Oleic Acid

Cited by 9 publications

References 0 publications

Effect of modulators on prostasome membrane‐bound ATPase in human seminal plasma

Effect of modulators on prostasome membrane‐bound ATPase in human seminal plasma

A stable model of respiratory distress by small injections of oleic acid in pigs

Action of long-chain fatty acids in vitro on Ca2+-stimulatable, Mg2+-dependent ATPase activity in human red cell membranes

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