Intestinal iron transport: studies using a loop of gut with an artificial circulation

Abstract

After the aorta and portal vein in rats were cannulated, buffered physiological solution containing dextran was circulated through the intestinal vascular system. Iron labeled with Fe59 was introduced into an isolated duodenal loop, and the transfer into the venous effluent studied. The effect of varying the dose and valency of the Fe in the lumen was found to be similar to previously reported observations on Fe absorption in vivo. When the pH of the luminal contents was lowered, transfer was markedly increased. Anoxia and several metabolic poisons depressed Fe transfer, whereas methylene blue, [alpha]- ketoglutaric acid, and citric acid increased it. It was therefore concluded that Fe transfer across the intestinal mucous membrane is an active metabolic process. Previous in vivo manipulation of the test animals, such as venesection or alteration of the Fe content of the diet, influenced the behavior of the artificial preparation. These observations may therefore be added to the existing evidence indicating that a degree of control over iron absorption resides in the mucosal cells of the upper small intestine.