Vitamin D: A cholecalciferol metabolite highly active in promoting intestinal calcium transport.
A major polar metabolite of cholecalciferol (vitamin D(3)) obtained from chick intestines is over four times as effective as cholecalciferol and over two times as effective as 25-hydroxycholecalciferol in stimulating intestinal calcium transport 24 hours after administration. Following a considerable lag, cholecalciferol and its 25-hydroxy derivative produce a maximum stimulation of the transport response at 24 to 48 hours. The polar intestinal metabolite greatly shortens this lag, stimulating maximum calcium transport by 9 hours. At 9 hours this metabolite is at least 13 times as active as the parent cholecalciferol and as such is a likely candidate for the biologically active form of cholecalciferol in the intestine.
D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D002762:Cholecalciferol / Q000378:metabolism / Q000494:pharmacology*; D007422:Intestines / Q000187:drug effects*; D013997:Time Factors
D002762:Cholecalciferol; D002118:Calcium