oleoyl-coenzyme-a and Vitamin-D-Deficiency

The role of the fatty-acid composition of the intestinal brush-border membrane in the control of transmembrane Ca2+ transport was examined by in vitro acylation of endogenous phospholipids. The initial rate of Ca2+ uptake into brush-border membrane vesicles was stimulated 1.6-fold by incubation with 50 microM linoleoyl CoA, which was the most effective CoA ester examined. Oleoyl CoA was also active, but stearoyl CoA, palmitoyl CoA and arachidonyl CoA displayed no activity. The effect of linoleoyl CoA was specific for Ca2+ transport; sodium-dependent phosphate uptake was slightly inhibited and the activity of alkaline phosphatase, a brush-border enzyme, was unaffected. Incubation of brush-border vesicles with either stimulatory (oleate) or nonstimulatory (stearate) CoA esters resulted in the incorporation of fatty acid into the four major phospholipid classes, suggesting a fatty-acid specificity of the Ca2+ transport phenomenon. These results are consistent with the hypothesis that fatty acids are important elements in the control of brush-border Ca2+ transport.

Topics: Acyl Coenzyme A; Animals; Biological Transport; Calcium; Chickens; Fatty Acids; Intestinal Mucosa; Male; Membrane Lipids; Microvilli; Vitamin D Deficiency