Active transport of Fe⁵⁹ by everted segments of rat duodenum

Abstract

Everted gut sacs prepared from segments of the proximal small intestine of rats transport Fe 59 from the mucosal to the serosal surfaces against concentration gradients in vitro. The active transport mechanism is dependent upon oxidative metabolism and the generation of phosphate-bond energy, and is limited in capacity. The active transport process is maximal in the region of the small intestine immediately distal to the pylorus and diminishes with more distal segments of the gut. Addition of ascorbic acid to the incubation medium markedly increases the active transport of Fe 59 in vitro.