Metabolic Basis of Calcium and Strontium Discrimination Studies with Surviving Intestinal Segments

The differential movement of Ca/sup 45/ and Sr/sup 85/ across surviving intestinal segments of the rat was studied. In the duodenal segment, Ca/sup 45/ but not Sr/sup 85/ was transported against a concentration gradient from mucosa to serosa. In the ileal segment, Sr/sup 85/ but not C a/sup 45/ was transferred against a concentration granient from serosa to mucosa. Incubation of segments at 0 deg C under N/sub 2/, or in presence of metabolic inhibitors eliminated active transpont and eliminated strontium-calcium discrimination. Ca-Sr discrimination under given conditions was dependent upon a metabolically active membrane. (auth)