Abstract
The effect of 1α-hydroxyvitamin D_3 (1α-OH-D_3) on the intestinal Ca transport and serum Ca level were studied in vitamin D deficient anephric rats. Intestinal Ca transport was stimulated by a dose of 312 pmol of 1α-OH-D_3 in anephric rats as well as sham operated rats, whereas serum Ca level was not changed by the dose. Increasing the amounts of 1α-OH-D_3 to 6,250 pmol, the effect on serum Ca level was observed. These results suggest that 1α-OH-D_3 is less effective on the mobilization of Ca from bone but is effective on intestinal Ca transport. From these points, the some possibility of the presence of unidentified active vitamin D_3 metabolites on bone was discussed.
