Lack of effect on ovariectomy on the metabolism of vitamin D and intestinal calcium-binding protein in female rats.
The metabolism of 25-hydroxycholecalciferol (25-(OH)D3), plasma concentration of 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) and the amount of calcium-binding protein (CaBP) in duodenal mucosa were determined in ovariectomized rats and were compared with data observed in normal age-matched cyclic rats. Sephadex LH-20 and high-pressure liquid chromatography were used for the study of the metabolism of 25-(OH)D3. The concentration of 1,25-(OH)2D3 in plasma and prolactin in serum were measured by radioimmunoassay. Calcium-binding protein in duodenal mucosa was determined immunologically using electroimmunodiffusion. The results showed that the lack of ovarian hormones and low prolactin levels observed in ovariectomized rats did not promote a significant change in the metabolism of 25-(OH)D3, in the levels of 1,25-(OH)2D3 in the circulation or in the amount of CaBP in duodenal mucosa. It is possible that the regulation of 25-(OH)D3 by sex hormones is restricted to the state of calcium stress such as during egg-laying in birds or pregnancy and lactation in mammals.
D000818:Animals; D001835:Body Weight; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002369:Castration; D004032:Diet; D004100:Dihydroxycholecalciferols / Q000097:blood; D004386:Duodenum / Q000378:metabolism*; D005260:Female; D006887:Hydroxycholecalciferols / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism*; D011388:Prolactin / Q000097:blood; D051381:Rats; D014807:Vitamin D / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D004100:Dihydroxycholecalciferols; D006887:Hydroxycholecalciferols; D014807:Vitamin D; D011388:Prolactin