Influence of cholecalciferol (vitamin D(3)) on the initial kinetics of the uptake of calcium ions by rat small-intestinal mucosa (Short Communication).

The uptake of Ca(2+) by isolated small-intestinal mucosa from vitamin D-depleted and -repleted rats was analysed for the effects of vitamin D on initial kinetics. The rapid association of Ca(2+) with the tissue, which is complete within 1min, was unaffected by the vitamin, whereas the subsequent, linear, uptake was significantly increased. Neither the tissue space accessible to inulin nor the permeability to thiourea was influenced by vitamin D treatment.