Altered desaturase activities and fatty acid composition in liver microsomes of spontaneously diabetic Wistar BB rat

Abstract

We examined the activities of delta 9, delta 6 and delta 5 desaturases and fatty acid composition of liver microsomes in the insulin-dependent spontaneously diabetic adult female Wistar Bio-Breeding (BB) rat. The diabetic BB rats were subcutaneously injected with different doses of protamine zinc insulin in order to be killed in hyper-, normo- or hypo-glycemic states. Desaturase activities, which are partially inhibited by spontaneous diabetes during the normo- and hyper-glycemic periods, were similarly affected by the various insulin treatment; delta 9 desaturase activity being more depressed than the desaturase activities of either delta 6 of delta 5. Insulin treatment with 10 I.U./kg body weight twice a day for 2 days was able to restore the delta 9, delta 6 and delta 5 desaturase activities to control levels during the hypoglycemic period. The microsomal fatty acid composition of BB rats liver was not consistent with the desaturase activities, particularly delta 9 desaturase activity, during the different states of glycemia, indicating that they are not closely linked in a direct cause-effect relationship.