Biological Activity of 1alpha-hydroxycholecalciferol, a Synthetic Analog of the Hormonal Form of Vitamin D3
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1,25-Dihydroxycholecalciferol, the apparent active hormonal form of cholecalciferol (vitamin D(2)), is formed from cholecalciferol by specific and sequential hydroxylations of the sterol at carbons 25 and 1. Recently, 1alpha-hydroxycholecalciferol was synthesized and we report on its biological activity in rachitic chicks. 1alpha-Hydroxycholecalciferol is identical in potency to 1,25-dihydroxycholecalciferol in stimulation of intestinal calcium absorption; either sterol elicits a near maximal effect at a dose of 0.3-0.6 nmol. The time-course of action of 1alpha-hydroxycholecalciferol also parallels that of the active metabolite 1,25-dihydroxycholecalciferol with a maximal increase in calcium transport occurring 5-10 hr after administration of sterol to vitamin D-deficient chicks. 6.5 nmol of 1alpha-hydroxycholecalciferol causes a doubling in calcium absorption in only 2-3 hr, which is the most rapid physiologic response yet detected for a vitamin D-sterol. 1alpha-Hydroxycholecalciferol is active also in enhancing bone calcium resorption and, like 1,25-dihydroxycholecalciferol, is at least 10 times as active as cholecalciferol in mobilizing bone calcium and raising plasma calcium concentration. It is concluded that 1alpha-hydroxycholecalciferol represents a synthetic analog of 1,25-dihydroxycholecalciferol that can be used both to study the mechanism of action of this hormone and as a therapeutic agent in the treatment of patients with certain metabolic bone diseases.
Ghaderi Nik M, Mahdavi R, Ghazi S, Gholami K Poult Sci. 2024; 104(1):104618.
PMID: 39637655 PMC: 11665307. DOI: 10.1016/j.psj.2024.104618.
Warren M, Livingston K Curr Dev Nutr. 2021; 5(5):nzab018.
PMID: 33977215 PMC: 7929256. DOI: 10.1093/cdn/nzab018.
Warren M, Vu T, Toomer O, Fernandez J, Livingston K Front Vet Sci. 2020; 7:245.
PMID: 32587863 PMC: 7299047. DOI: 10.3389/fvets.2020.00245.
Desmarchelier C, Margier M, Preveraud D, Nowicki M, Rosilio V, Borel P Nutrients. 2017; 9(10).
PMID: 29065536 PMC: 5691768. DOI: 10.3390/nu9101152.
Alfacalcidol enhances collagen quality in ovariectomized rat bones.
Nagaoka H, Terajima M, Yamada S, Azuma Y, Chida T, Yamauchi M J Orthop Res. 2014; 32(8):1030-6.
PMID: 24809324 PMC: 4071133. DOI: 10.1002/jor.22642.