Dietary lipids modify intestinal lipid-binding protein RNA abundance in diabetic and control rats.

Background: Lipid-binding proteins have been identified in the enterocyte, including the cytosolic intestinal and liver fatty acid binding proteins (I-FABP and L-FABP, respectively) as well as the brush border membrane fatty acid transporter (FAT). It is unclear whether variations in the type of dietary lipids or diabetes modify the RNA abundance of these proteins. Diabetes is associated with an increased intestinal lipid uptake, and the lipid uptake is greater in rats fed a semisynthetic saturated fatty acid (SFA) as compared with a polyunsaturated fatty acid (PUFA) diet.

Methods: Male Sprague-Dawley rats were injected with streptozotocin or control vehicle and fed chow or either SFA or PUFA for 2 weeks. Northern blotting was performed on RNA isolated from jejunal and ileal tissues.

Results: In controls, feeding SFA as compared with PUFA reduced the jejunal abundance of I-FABP and L-FABP RNA. In diabetic rats, feeding SFA increased the ileal FAT RNA. Feeding PUFA reduced jejunal L-FABP and ileal FAT RNA in diabetic rats as compared with controls.

Conclusions: The enhanced lipid uptakes reported with feeding an SFA diet or with diabetes were not associated with parallel alterations in lipid-binding proteins. We speculate that these lipid-binding proteins act as a storage mechanism for lipids in enterocytes and are not directly involved in lipid uptake.