Effect of Dietary Vitamin D3 and Cadmium on the Lipid Composition of Rat Intestinal Brush Border Membranes

Vitamin D deficiency in cadmium-exposed rats was observ-ed along with enhanced tissue cadmium accumulation. In relation to the barrier function, the changes in the lipid composition have been studied in the intestinal brush border membranes prepared from rats raised on diets differing in vitamin D status in the absence or presence of cadmium. In an analysis of lipid composition, vitamin D3 treatment resulted in an increase of phospholipid content, and cadmium ingestion resulted in a decrease of cholesterol and glycolipid contents in the duodenal brush border membranes. On the other hand, vitamin D3 and cadmium showed no significant effect on the lipid composition of the jejunal brush border membranes. Further analysis of the fatty acid composition in duodenal brush border membrane lipids showed that vitamin D3 treatment led to an increase of the proportion of fatty acids (18:1 and 18:2 in the total and phospholipid fraction) and also shorter chain fatty acids in neutral lipid fractions in the absence of cadmium. However, vitamin D3 treatment in the presence of cadmium led to a decrease of the proportion of fatty acid (18:2 in the total and phospholipid fraction) and also shorter chain fatty acids in neutral lipid fractions. Vitamin D-dependent alterations of the membranes might act as a barrier in cadmium-exposed rats.