Absorption and Secretion in the Rabbit Duodenum and Ileum 1

Abstract

Summary

In both rabbit duodenum and ileum there was secretion of HCO₃ ^- into, and absorption of Cl^- from, the lumen. The transport of both anions decreased with increasing luminal fluid [HCO₃ ^-]. The net fluxes of Na⁺, K⁺, Cl^-, and HCO₃ ^- accounted for the movement of a near isotonic fluid, whether absorbed or secreted. In both duodenum and ileum luminal fluid [Cl^- + HCO₃ ^-] and conductivity decreased. The data are consistent with the secretion of soluble anionic mucosubstances, of low mobility, into both areas of the gut.