title: In vitro formation of 25-hydroxyvitamin D3 metabolites in endometrium: dependence on the hormonal status of the rat.
abstract: Rat myometrial tissue and endometrial cells were incubated with labeled 25-hydroxyvitamin D3 ([3H-26,27] 25OHD3) for 70 min at 37 C, and the resulting metabolites were isolated by sequential Sephadex LH-20 chromatography and high performance liquid chromatography. Two peaks more polar than 25OHD3 were present on the Sephadex LH-20 chromatograms. One of these metabolites had an identical chromatographic behavior on three different HPLC systems and an identical sensitivity to periodate cleavage as biosynthetic [3H-26,27] 24,25-dihydroxyvitamin D3 ([3H-26,27]24,25-(OH)2D3]. The in vitro production of this putative 24,25-(OH)2D3 was significantly higher in castrated animals than in normal adult rats. Treatment of rats with 17 beta-estradiol and/or medroxyprogesterone acetate reversed the effect of ovariectomy on 25OHD3 conversion. The in vitro production of the putative 24,25-(OH)2D3 was low during the estrous cycle and the initial stage of pregnancy. A dramatic increase in its production was observed on days 12 and 14 of pregnancy. 25OHD3 conversion was higher in endometrium than in myometrium under every experimental condition tested. These results demonstrate the ability of rat uterine tissue to convert 25OHD3 into more polar derivatives in vitro, and show the influence of the hormonal status of the rat on this in vitro capacity.
mesh_terms: D015650:24,25-Dihydroxyvitamin D 3; D000818:Animals; D002112:Calcifediol / Q000378:metabolism*; D004100:Dihydroxycholecalciferols / Q000378:metabolism; D004717:Endometrium / Q000378:metabolism*; D004958:Estradiol / Q000097:blood; D004971:Estrus; D005260:Female; D009215:Myometrium / Q000378:metabolism; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D004100:Dihydroxycholecalciferols; D015650:24,25-Dihydroxyvitamin D 3; D011374:Progesterone; D004958:Estradiol; D002112:Calcifediol