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

Abstract

We examined the activities of Δ9, Δ6 and Δ5 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; Δ9 desaturase activity being more depressed than the desaturase activities of either Δ6 of Δ5. Insulin treatment with 10 I.U./kg body weight twice a day for 2 days was able to restore the Δ9, Δ6 and Δ5 desaturase activities to control levels during the hypoglycemie period. The microsomal fatty acid composition of BB rats liver was not consistent with the desaturase activities, particularly Δ9 desaturase activity, during the different states of glycemia, indicating that they are not closely linked in a direct cause-effect relationship.