Transporte de glutamina, alamina e glicose em mucosa intestinal de coelhos: $b proposta de um modelo matemático para as curvas dose-resposta

Abstract

Dehydration and malnutrition are the imediate cause of diarrheal diseases. To investigate the biological significance of glutamine, alanine and glucose on the transport of cation in the intestinal mucosal membrane we use the Ussing chamber model. The intestinal transport was measure by short-circuit current (Isc), potential difference (PD) and tissue resistance (TR) on control and mucosal treated with cholera toxin. Increasing doses (IO-5 to 10’1 M) of glutamine, alanine and glucose on the mucosa side cause a significante increase in the intestinal cation cotransport. Although glucose causes an earlier effect, glutamine (30 mM) and alanine (100 mM) increase twice as more the maximum effect of glucose (30 mM). The kinetic of the dose-response curves suggest that the intestinal mucosal transport of alanine is different from glutamine and glucose. The kinetic for glutamine and glucose are similar, however, the efficacy of the intestinal cotransport system for glutamine is greater than alanine and glucose. Replacing equimolar sodium by choline on luminal side, completely abolish the intestinal effects of glutamine, alanine and glucose. The addition of alanine or glutamine, but not glucose, on the serosal side cause increase on sodium cotransport, which was additive only for alanine when added on both sides (mucosal and serosal).