J. Mchowat et al., Induction of Ca-independent PLA(2) and conservation of plasmalogen polyunsaturated fatty acids in diabetic heart, AM J P-ENDO, 279(1), 2000, pp. E25-E32
Citations number
31
Categorie Soggetti
Endocrinology, Nutrition & Metabolism
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM
Diabetes-induced changes in phospholipase A(2) (PLA(2)) activity have been
measured in several tissues but are undefined in diabetic myocardium. We me
asured ventricular PLA(2) activity in control, streptozotocin-induced diabe
tic, and insulin-treated diabetic rats and characterized myocardial phospho
lipids to determine whether diabetes altered myocardial phospholipid metabo
lism. Increased membrane-associated Ca2+-independent PLA(2) (iPLA(2)) activ
ity was observed in diabetes that was selective for arachidonylated phospho
lipids. Increased iPLA(2) activity was accompanied by an increase in cholin
e lysophospholipids. Diabetes was associated with marked alterations in the
phospholipid composition of the myocardium, characterized by decreases in
esterified arachidonic and docosahexaenoic acids and increases in linoleic
acid. The decrease in polyunsaturated fatty acids was confined to diacylpho
spholipids, whereas the relative amount of these fatty acids in plasmalogen
s was increased. Diabetes-induced changes in PLA(2) activity, lysophospholi
pid production, and alterations in phospholipid composition were all revers
ed by insulin treatment of diabetic animals. Diabetesinduced changes in mem
brane phospholipid content and phospholipid hydrolysis may contribute to so
me of the alterations in myocardial function that are observed in diabetic
patients.