Effect of short-chain fatty acids on calcium absorption by the rat colon.

An in vivo luminal perfusion technique was used to investigate whether short-chain fatty acids influence the absorption of Ca by the rat colon. Na and water absorption were also determined. In the distal colon, acetate and butyrate caused a significant increase in Ca absorption, while the absorption of Na and water were not affected. In the proximal colon, butyrate did not influence Ca absorption, but significantly enhanced Na and water absorption. These results are in part consistent with the presence of a Ca-H exchanger in the apical membrane of the distal colon mediating Ca uptake into the epithelial cell.