MODULATION OF MONKEY SMALL-INTESTINAL BRUSH-BORDER MEMBRANE D-GLUCOSETRANSPORT BY NONESTERIFIED FATTY-ACIDS

Brush border membranes isolated from monkey intestinal mucosa was foun d to contain considerable amount of nonesterified fatty acids. Incubat ion of brush border membranes with fatty acid free albumin selectively removed the free fatty acids more than 80% without altering the level of phospholipids or cholesterol. The sodium dependant D-glucose trans port was stimulated by the albumin treatment. Kinetic study showed tha t albumin treatment did not alter the apparent affinity (K(m)) of the transporter for glucose whereas the maximal velocity (V(max)) was incr eased significantly. The sodium dependent D-glucose transport was inhi bited by the exogenously added unsaturated fatty acids. Saturated fatt y acids and methyl esters of unsaturated fatty acids showed no inhibit ion. Based on these results, it may be concluded that free fatty acids inhibit the sodium dependant intestinal D-glucose transport either by directly interacting with the transport protein or by abolishing the sodium gradient.