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Studies on Infant Diarrhea. V. Mechanisms of the Impaired Jejunal Absorption

1970; Springer Nature; Volume: 4; Issue: 5 Linguagem: Inglês

10.1203/00006450-197009000-00170

1530-0447

Carmen Lugo-de-Rivera, Helen Rodriguez-de-Curet, Ramon Torres‐Pinedo, Antonio Ortiz,

Clinical Nutrition and Gastroenterology

Studies on infants with diarrhea and in recovery have shown that there is impaired jejunal absorption of carbohydrates. It is not known whether this malabsorption is due to interference with normal active transport processes or to alternations in the permeability characteristics of the intestinal mucosa. To clarify this, the following experiments were undertaken. A series of perfusion studies with amino acids and hexoses were performed on 12 infants with acute diarrhea and on 18 infants who were either normal or in the process of recovery. Absorption velocities were lower in diarrhea and the response to increasing concentrations tended to follow a saturation pattern. In recovery, the response to increasing concentrations was linear and Km and Vmax values could not be calculated. These results suggest that in vivo, the rapid removal of substrate from the that in vivo, the rapid removal of substrate from the mucosal cell by the circulation is a factor which markedly modifies the kinetics of absorption. A probale explanation of the impaired jejunal absorption in diarrhea is a derangement in the permeability characteristics of the mucosa which results in intracellular accumulation of the absorbed substrate.