25-hydroxycholecalciferol: direct effect on calcium transport.
The perfused small intestine from a vitamin D deficient rat exhibits about one-half the calcium transport of the intestine from a rat given vitamin D. These levels of calcium transport can be maintained for at least 4 hours. Addition of 2.5 micrograms of 25-hydroxycholecalciferol added to the vitamin D deficient intestine via the arterial blood perfusate induces a rise in calcium transport to +D levels within 2 hours. In contrast, 250 micrograms of vitamin D(3) given in the same manner has no effect on the calcium transport level overa 4-hour period. These data provide strong evidence that 25-hydroxycholecalci ferol represents the metabolically active form of vitamin D(3).
D000818:Animals; D001692:Biological Transport / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism*; D002127:Calcium Isotopes; D002762:Cholecalciferol / Q000494:pharmacology*; D007421:Intestine, Small / Q000187:drug effects*; D010477:Perfusion; D051381:Rats; D014808:Vitamin D Deficiency / Q000378:metabolism*
D002127:Calcium Isotopes; D002762:Cholecalciferol; D002118:Calcium