Dietary mold oil rich in gamma linolenic acid increases insulin-dependent glucose utilization in isolated rat adipocytes

Abstract

Effects of dietary fats differing in fatty acid composition on insulin-stimulated glucose metabolism in adipocytes isolated from rat white adipose tissue were compared. Rats were fed experimental diets containing various fats differing in fatty acid composition for 7 days. In the first experiment, rats were fed palm oil mainly consisting of palmitic (45.3%) and oleic acids (39.1%) or safflower oil rich in linoleic acid (71.6%). In the second trial, rats were fed palm oil, or a fat mixture rich in linoleic acid or mold oil rich in γ-linolenic acid. Contents of fatty acids except for linoleic and γ-linolenic acid were comparable between the fat mixture and mold oil. The former was devoid of γ-linolenic acid and contained 42.0% linoleic acid, while the latter contained 25.9% γ-linolenic and 15.7% linoleic acids. In the first experiment, the insulin-dependent increase in glucose oxidation and incorporation into lipids was higher in rats fed safflower oil compared to those fed palm oil. In the second experiment, the insulin-dependent increase in glucose oxidation and incorporation into lipids was higher in rats fed the fat mixture and mold oil than in those fed palm oil. However, the extent of the increase in these parameters was much greater in rats fed mold oil than in those fed the fat mixture. Therefore, dietary γ-linolenic acid compared to linoleic acid increases glucose metabolism in response to insulin stimuli in isolated rat adipocytes.