Adrenic acid delta4 desaturation and fatty acid composition in the liver of marine-oil fed streptozotocin diabetic rats.

The aim of the present study was to assess the effect of streptozotocin diabetes and insulin treatment on adrenic acid delta4 desaturation and fatty acid composition of liver microsomes in Wistar rats fed a fat free semi-synthetic basal diet supplemented with 10% EPA-rich marine oil. Results showed that, in liver microsomes of hyperglycemic rats, the 22:6n-3/22:5n-3 ratio in total lipids was elevated and desaturation of adrenic acid to n-6 docosapentaenoic acid was enhanced. Insulin treatment with 2.0 I.U./100 g body weight-1 twice a day for 3 days resulted in hypoglycemia and suppressed both the increased delta4 n-6 desaturation and 22:6n-3/22:5n-3 ratio. It is concluded that the delta4 desaturation enzyme system, which is activated by experimental diabetes, is regulated by mechanisms different from those regulating delta6 and delta5 desaturations.