The intestinal profile of Na-K-ATPase in two rat models of acute renal failure.

The specific activity of mucosal Na-K-ATPase in segments of the small intestine and colon was examined after BN or BUL. BN resulted in a surge of the specific activity of the enzyme throughout the mucosa of the intestinal tract (duodenum 26%, jejunum 33%, ileum 37%, and colon 68%). BUL induced to significant change in the specific activity of Na-K-ATPase in the small intestinal mucosa and a small rise (32%) in the specific activity of the enzyme in the colon. Kinetic analyses of potassium activation of the enzyme in the two models of ARF indicate that the increase in the specific activity of the enzyme in the colonic mucosa was a function of increased Vmax rather than a change in the apparent Km for potassium by the Na-K-ATPase. It is theorized that the kidney modifies the response of intestinal Na-K-ATPase in AFR.