Experimental diabetes reduces circulating 1,25-dihydroxyvitamin D in the rat.
Duodenal calcium absorption and a vitamin D-dependent duodenal calcium-binding protein are depressed in rats with alloxan- or streptozotocin-induced diabetes. To test for possible abnormal vitamin D metabolism in diabetes we measured serum concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D in control, streptozotocin diabetic, and insulin-treated diabetic rats. The serum concentration of 1,25-dihydroxyvitamin D was depressed in untreated diabetic rats to one-eighth of the level in controls and was restored to control levels by insulin treatment. The serum concentration of 25-hydroxyvitamin D was the same in all three groups. Hence, effects of diabetes on duodenal calcium transport can be explained by reduced concentrations of 1,25-dihydroxyvitamin D resulting either from failure of renal 1alpha-hydroxylation of 25-hydroxyvitamin D or increased catabolism of 1,25-dihydroxyvitamin D.
D000818:Animals; D003920:Diabetes Mellitus / Q000097:blood* / Q000139:chemically induced / Q000188:drug therapy; D004100:Dihydroxycholecalciferols / Q000097:blood*; D006887:Hydroxycholecalciferols / Q000097:blood*; D007328:Insulin / Q000627:therapeutic use; D008297:Male; D051381:Rats; D013311:Streptozocin
D004100:Dihydroxycholecalciferols; D006887:Hydroxycholecalciferols; D007328:Insulin; D013311:Streptozocin