title: Studies on vitamin D metabolism: catabolism of 1 alpha, 25-dihydroxyvitamin D3 and 1 alpha-hydroxyvitamin D3 to a metabolite inactive on bone mineral mobilization.
abstract: A heretofore unknown metabolite of vitamin D3 was isolated from the 1 alpha, 24, 25-trihydroxyvitamin D3 fraction of lipid extracts obtained from plasma of rats which were given intravenous or oral doses of 100 pmol/100 g of either 1 alpha-hydroxyvitamin D3 or 1 alpha, 23-dihydroxyvitamin D3. Doses of 25-250 pmoles of the new metabolite when given to a vitamin D deficient rat were completely inactive in terms of stimulating the classic vitamin D response of bone calcium mobilization. The nature of the metabolism of 1 alpha-hydroxyvitamin D3 or 1 alpha, 25-dihydroxyvitamin D3 to the metabolite is not clear at the present time, but it is probable that neither of these steroids undergo side-chain cleavage to yield the new metabolite.
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000378:metabolism*; D002117:Calcitriol; D002118:Calcium / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D004100:Dihydroxycholecalciferols / Q000378:metabolism*; D006887:Hydroxycholecalciferols / Q000378:metabolism*; D008297:Male; D051381:Rats; D014807:Vitamin D / Q000378:metabolism*
chemical_list: D004100:Dihydroxycholecalciferols; D006887:Hydroxycholecalciferols; D014807:Vitamin D; D002117:Calcitriol; D002118:Calcium; C008088:alfacalcidol