[Effects of different metabolites of vitamin D3 and of calcium concentration on the intestinal absorption of strontium].

The effect of calcium concentration and vitamin B3 25 OHD3 and 1.25 diOHD3 upon intestinal strontium transport was studied in vitamin D deficient rats with duodenal perfusion in situ. When the calcium concentration was increased, the strontium passive absorption was decreased. The vitamin D3 and its derivatives increased intestinal strontium transport significantly and this increment was not modified by calcium. In our experiment, calcium is competitive with strontium only in passive absorption.