title: Phospholipase A activity of cultured rat ventricular myocyte is affected by the nature of cellular polyunsaturated fatty acids.
abstract: Fatty acid composition of membrane phospholipids of cultured cardiomyocytes can be modified by the type of polyunsaturated fatty acids (n-3 or n-6 PUFA) constituting the culture medium. In this study, we investigated the effect of fatty acid modification on the activities of the key enzymes involved in the deacylation-reacylation cycle of membrane phospholipids. Results showed that cardiomyocytes grown in the presence of n-6 PUFA exhibited a higher specific alkaline phospholipase A (mainly A2) activity (+34%) and a moderately lower lysophospholipase activity (-17%) than when incubated with n-3 PUFA. AcylCoA:lysophosphatidylcholine acyltransferase, acid lysosomal phospholipase A1 and acylCoA synthetase activities were not significantly altered by changes in cellular PUFA composition. It was demonstrated that the differences between phospholipase A activities of the two types of cultured cells were linked neither to a differential leakage of enzyme nor to oxidative injury to the enzyme through blockage of essential sulfhydryl groups. One likely explanation is that the PUFA-induced changes in membrane composition alter membrane physical properties which, in turn, affect membrane-bound phospholipase A activity. Possible beneficial effects of the n-3 PUFA-induced changes on membrane stability are discussed.
authors.affiliation: Institut National de la Sante et de la Recherche Medicale, Unite 130, Marseille, France.
authors.forename: G
authors.initials: G
authors.lastname: Nalbone
authors.forename: A
authors.initials: A
authors.lastname: Grynberg
authors.forename: A
authors.initials: A
authors.lastname: Chevalier
authors.forename: J
authors.initials: J
authors.lastname: Leonardi
authors.forename: E
authors.initials: E
authors.lastname: Termine
authors.forename: H
authors.initials: H
authors.lastname: Lafont
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D008563:Membrane Lipids / Q000378:metabolism*; D009206:Myocardium / Q000201:enzymology* / Q000378:metabolism; D010740:Phospholipases / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism*; D054466:Phospholipases A1; D010743:Phospholipids / Q000378:metabolism; D051381:Rats
chemical_list: D005231:Fatty Acids, Unsaturated; D008563:Membrane Lipids; D010743:Phospholipids; D010740:Phospholipases; D010741:Phospholipases A; D054466:Phospholipases A1