The Turnover of Intestinal Epithelium in the Chick

THE cells of the intestinal epithelium originate in the crypts of Lieberkuhn and migrate up the sides of the villi. When they reach the tips (extrusion zone) of the villi the cells are extruded into the lumen of the intestine. The mechanism of migration is not fully understood, but the movement has been shown to be rapid. Leblond and Stevens (1948) reported that replacement of the epithelium in rats took 1.57 days in the duodenum and 1.35 days in the ileum. In cats, the renewal time was found to be 2.25 and 2.75 days for the duodenum and ileum, respectively (McMinn, 1954). In human duodenum, a renewal time of 1.8 days was reported by Bertalanffy and Nagy (1958). As part of investigations on avian digestion and absorption, the turnover of intestinal epithelium in chicks was studied. The movement of intestinal mucosal cells was followed using microradioautography after injecting chicks with …