1,25-Dihydroxyvitamin D3 increases the expression of the CaT1 epithelial calcium channel in the Caco-2 human intestinal cell line

These observations are the first to demonstrate regulation of CaT1 expression by vitamin D and are consistent with a new model of intestinal calcium absorption wherein vitamin D-mediated changes in brush border membrane CaT1 levels could be the primary gatekeeper regulating homeostatic modulation of intestinal calcium absorption efficiency.