title: Biological activity of 1 alpha, 25-dihydroxyvitamin D derivatives--24-epi-1 alpha, 25-dihydroxyvitamin D-2 and 1 alpha,25-dihydroxyvitamin D-7.
abstract: Biological activity of 24-epi-1 alpha,25-dihydroxyvitamin D-2 (24-epi-1,25(OH)2D2) and 1 alpha,25-dihydroxyvitamin D-7 (1,25(OH)2D7), the 22,23-dihydro derivative of the former compound, was investigated. Both of the vitamin D derivatives stimulated intestinal calcium transport and calcium mobilization from bones in rats; however, the effect was about 50% of that of 1 alpha,25-dihydroxyvitamin D-3 (1,25(OH)2D3). On the other hand, 24-epi-1,25(OH)2D2 and 1,25(OH)2D7 inducement of HL-60 human leukemia cell differentiation was comparable to that of 1,25(OH)2D3. Accordingly, the differentiation-inducing activity of 24-epi-1,25(OH)2D2 and 1,25(OH)2D7 was much greater than their ability to stimulate calcium metabolism. In contrast to 1,25(OH)2D3, 24-epi-1,25(OH)2D2 and 1,25(OH)2D7 exerted little hypercalcemic activity in mice. These results suggest that both vitamin D derivatives will be useful as anti-tumor agents.
authors.affiliation: Department of Geriatrics, Faculty of Medicine, University of Tokyo, Japan.
authors.forename: F
authors.initials: F
authors.lastname: Sato
authors.forename: Y
authors.initials: Y
authors.lastname: Okamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Ouchi
authors.forename: M
authors.initials: M
authors.lastname: Kaneki
authors.forename: T
authors.initials: T
authors.lastname: Nakamura
authors.forename: N
authors.initials: N
authors.lastname: Ikekawa
authors.forename: H
authors.initials: H
authors.lastname: Orimo
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001842:Bone and Bones / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line / Q000187:drug effects / Q000378:metabolism; D004872:Ergocalciferols / Q000494:pharmacology*; D006801:Humans; D006934:Hypercalcemia / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D051381:Rats; D011919:Rats, Inbred Strains; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D004872:Ergocalciferols; D014807:Vitamin D; C003564:1,25-dihydroxyergocalciferol; D000469:Alkaline Phosphatase; D002118:Calcium