Dietary fat saturation alters diabetic rat brush border membrane phospholipid fatty acid composition

Alteration in dietary fatty acid composition produces changes in brush border membrane (BBM) fatty acid composition and changes in nutrient transport. Feeding a highly polyunsaturated fatty acid diet (P) reduces glucose uptake in diabetic rats to near control levels, whereas feeding a highly saturated fatty acid diet (S) enhances glucose uptake. Female Wistar rats were placed onto either a P or S diet for 5 weeks, injected with streptozotocin and continued on their respective diets for an additional 3 weeks. BBM were isolated, purified and extracted for analysis of fatty acyl constituents of phosphatidylcholine (PC) and phosphatidylethanolamine (PE). In jejunal and ileal BBM PC and PE, feeding S was associated with a decrease in total omega 6 fatty acids (18:2 omega 6), and an increase in the ratio of monounsaturated/saturated fatty acids as compared with animals fed P. In jejunal BBM PC and PE, the ratio of 18:2 omega 6/20:4 omega 6 was reduced in animals fed S as compared with those fed P. Diabetes was associated with fewer changes in BBM fatty acid composition in animals fed P as compared with those fed S. Feeding P to diabetic animals prevents the changes in BBM fatty acid composition observed when animals are fed S. Alterations in BBM lipid composition may be related to the enhanced permeability to glucose in animals fed S, while the similarity of BBM fatty acid composition in diabetic and control animals fed P may be related to the similar glucose uptake. The mechanisms controlling BBM lipid composition require further investigation, and may be important for the development of nutritional strategies for the control of diabetes.