Cotransport of sodium with glutamine alanine and glucose in the isolated rabbit ileal mucosa

RESUMO

To investigate the effect of substrates during oral rehydration therapy, we studied intestinal cation cotransport (ICC) with glutamine (Gln) alanine (Ala) and glucose (Glu). The specific aims were to determine the biological effects of these three different cotransport systems on intestinal function. Isolated rabbit ileal mucosa preparations mounted in Ussing chambers were studied. ICC was determined by measuring short-circuit current (Isc) and potential difference (PD) while monitoring toissue resistance (TR). The data are reported as the mean ñ SEM of 4-6 experiments for each amino acid concentration. Increasing concentrations of Gln (10-5 to 10-2 M), Ala (10-5 to 10-1 M) and Glu (10-5 to 10-2 M) caused a significant (P<0.05) increase in ICC. Glin (30 mM) and Ala (0.1 M) had a maximal effects (Em (Glin)=100% anmd Em (Ala)=66%, P<0.05) which was higher than that obtained with 30 mM Glu (Em (Glu)=35%). When sodium was replaced with choline on the mucosal side. Ringer solution completeley abolished the response with Gln, Ala and Glu. The presence of all three substrates (10-2 M gln, 10-1 M Ala and 10-2 M Glu) in Ringer solution on the mucosal side caused a significant increase in ICC ( increase of short circuit current = III ñ 43 uA, P<0.05). These results demonstrate that Glin, Ala and Glu each increased sodium-dependent cation cotransport, and that sodium-dependent intestinal cation cotransport was higher with Gln than with Ala or Glu