Intestinal calcium and phosphate transport and intestinal alkaline phosphatase

The aim of the study was to investigate the link, if any, between alkaline phosphatase activity and intestinal calcium and phosphate transport using the hypophysectomized (HX) rat model. Ionic transport was evaluated by the in situ ligated loop technique. Hypophysectomy (HX) resulted in a decrease in both duodenal and jejunal alkaline phosphatase activity but did not alter the active transport of calcium and phosphate. Vitamin D depletion (-D), suppressed intestinal transport in the HX rat without altering alkaline phosphatase activity. Repletion of 1,25(OH)2D3 in the -DHX rat resulted in an increase in active transport of calcium and phosphate without altering the alkaline phosphatase activity. Thus, using the HX animal model, we were able to differentiate intestinal alkaline phosphatase activity from the overall intestinal transport of calcium and phosphate.