The effect of ATP on the transport of hexoses and amino acids in everted sacs of rat small intestine

Abstract

1. 1. The effects of exogenous ATP (5 mM) on the transport of hexoses and amino acids in everted sacs of rat small intestine have been studied. 2. 2. Mucosal ATP is inhibitory to net leucine, glycine and galactose transport, whether transport is expressed as mucosal transfer or final tissue concentration. 3. 3. The inhibition of transfer was specific to the ATP molecule; ADP, AMP, adenosine or adenine producing no effect. 4. 4. The inhibitory effect of ATP could be prevented if additional Ca 2+ or Mg 2+ was present in the incubation medium. The divalent cations themselves had no effect on transport. 5. 5. ATP stimulated the efflux of leucine and galactose from preloaded preparations. The stimulatory effect was specific to ATP and could be prevented by extra Mg 2+ in the incubation medium. 6. 6. The mechanisms by which ATP could influence transport processes are discussed and it is suggested that the results can best be explained by an action of ATP on the passive permeability of the intestinal preparation.