The stimulation of 1,25-dihydroxycholecalciferol metabolism in vitamin D-deficient rats by 1,25-dihydroxycholecalciferol treatment.
Daily oral administration of 1,25-dihydroxycholecalciferol to vitamin D-deficient rats increases the rate of disappearance of [(3)H]1,25-dihydroxycholecalciferol and increases the rate of appearance of metabolites both less polar and more polar than 1,25-dihydroxycholecalciferol in the intestine, bone, liver, kidney, plasma, and muscle. Since 1,25-dihydroxycholecalciferol is believed to be the metabolically active form of vitamin D in the stimulation of intestinal calcium transport and bone calcium mobilization, these results provide an explanation for the fact that daily oral administration of 1,25-dihydroxycholecalciferol is relatively ineffective in the maintenance of serum calcium and in the calcification of bone in rats.
D000284:Administration, Oral; D000818:Animals; D001842:Bone and Bones / Q000378:metabolism; D002118:Calcium / Q000097:blood / Q000378:metabolism; D006887:Hydroxycholecalciferols / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism* / Q000627:therapeutic use; D007275:Injections, Intravenous; D007413:Intestinal Mucosa / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D009132:Muscles / Q000378:metabolism; D051381:Rats; D014316:Tritium; D014808:Vitamin D Deficiency / Q000188:drug therapy / Q000378:metabolism*
D006887:Hydroxycholecalciferols; D014316:Tritium; D002118:Calcium