In patients with colectomy, epithelial transport function in the remnant small intestine can be regulated in response to the increased fecal electrolyte and fluid loss. Using a rat colectomy model, we investigated the Na⁺ and K⁺ transport mechanisms underlying the intestinal response. Proctocolectomy with ileoanal anastomosis was performed on rats. The small intestinal mucosa was mounted in Ussing chambers; then short-circuit currents and ²²Na⁺ fluxes were measured. mRNA expression of the epithelial Na⁺ channel (ENaC) was determined by Northern blotting. Amiloride-sensitive, electrogenic Na⁺ absorption appeared in the ileum after proctocolectomy. This functional change was accompanied by the chronological induction of mRNAs for -, -, and -subunits of the ENaC in the ileum. Tetraethylammonium-sensitive short-circuit current was also activated. We conclude that electrogenic Na⁺ absorption and probably K⁺ secretion are induced in the ileum after proctocolectomy. This induction of electrogenic Na⁺ absorption is probably mediated by the increase in the mRNA levels for all three types of subunits of the ENaC and may contribute to the recovery from the increased fecal Na⁺ loss.

aldosterone; potassium secretion; sodium absorption; intestinal adaptation; intestinal absorption

This article has been cited by other articles:

				D. Heitzmann and R. Warth Physiology and Pathophysiology of Potassium Channels in Gastrointestinal Epithelia Physiol Rev, July 1, 2008; 88(3): 1119 - 1182. [Abstract] [Full Text] [PDF]

				X.-H. Weng, K. W. Beyenbach, and A. Quaroni Cultured monolayers of the dog jejunum with the structural and functional properties resembling the normal epithelium Am J Physiol Gastrointest Liver Physiol, April 1, 2005; 288(4): G705 - G717. [Abstract] [Full Text] [PDF]