Bs. Alam et al., EFFECT OF REVERSAL OF DIET-INDUCED CHANGES IN ACYL GROUP COMPOSITION OF CARDIAC MEMBRANE-LIPIDS ON ADENYLATE-CYCLASE ACTIVITY IN RATS, Journal of nutritional biochemistry, 5(2), 1994, pp. 106-112
The purpose of the present investigation was to determine if the diet-
induced changes in cardiac adenylate cyclase activity and membrane lip
ids can be reversed. Three groups of male weanling Sprague-Dawley rats
were fed purified diets containing different fats: 9% butter (Btr) 1% corn oil (CO) (group 1), 10% CO (group II), and 9% ethyl ester conc
entrate of n-3 fatty acids (EEC) + 1% CO (group III). After 5 weeks of
feeding, rats from each group were killed. Cardiac membranes were pre
pared and assayed for adenylate cyclase activity. The fatty acid compo
sition of membrane total phospholipids was also determined. The remain
ing rats in group I were divided into four subgroups and fed the follo
wing diets for the reversal study: 9% Btr + 1% CO (group la), 9% EEC f
1% CO (group Ib), 10% CO (group Ic), and 7% Btr + 2% EEC + 1% CO (gro
up Id). Rats in groups II and III were maintained on their original di
ets. Rats were killed 5 weeks after changing the dietary regimes, and
membranes were prepared from heart and analyzed for their fatty acid c
omposition of total phospholipids. Adenylate cyclase activity (basal,
fluoride- and forskolin-stimulated) was also measured. The enzyme acti
vity was lower in membranes of rats in group la than those in groups I
I or III. Whereas the diet-induced changes in fatty acid composition w
ere essentially reversed by dietary modification (groups Ib and Ic), t
he changes in adenylate cyclase activity were only partially reversed.