Effect of cholesterol feeding and sex difference on the tissue n-6 and n-3 fatty acid levels in fat-deficient rats treated with linoleate or linolenate

Weanling rats of both sexes fed on a fat-free diet for 8 weeks were given 5 i.p. Injections every 48 hr of 60 mg/100 g body weight of pure ethyl linoleate (LA) or linolenate (LN) with or without 1% dietary cholesterol supplementation. Phospholipid fatty acid compositions in plasma and liver were examined. LA administration increased n-6 fatty acids while LN treatment increased n-3 fatty acids. Cholesterol feeding significantly reduced 20: 4n-6 in LA treated animals and 20: 5n-3 and 22: 6n-3 in LN treated animals. The reductions in males were significantly greater than in females suggesting that the sex difference modulates the cholesterol-induced reduction of n-6 and n-3 fatty acids.