title: 1, 25-Dihydroxycholecalciferol stimulates conversion of androstenedione into oestrone by human skin fibroblasts in culture.
abstract: Pre-incubation of monolayer cultures of human skin fibroblasts with 1,25-dihydroxycholecalciferol (1,25-D3; 0.1-10 nmol/l) increased the rate of conversion of androstenedione into oestrone (aromatase activity) when measured subsequently in the presence of a 5 alpha-reductase inhibitor (10 mumol/l). Maximal stimulation (14- to 89-fold with 10 nmol 1,25-D3/l) occurred 12 h after addition of the hormone and was maintained for up to 48 h. Stimulation was prevented by cycloheximide. In one cell line high 1,25-D3 concentrations (greater than 30 nmol/l) prevented the increase in aromatase activity; this did not appear to result from direct enzyme inhibition by 1, 25-D3. The possibility is considered that 1,25-D3 could act as a physiological regulator of peripheral aromatase. As oestrogens can prevent postmenopausal bone loss, it is speculated that 1,25-D3 might protect against bone resorption by maintaining peripheral oestrogen biosynthesis.
mesh_terms: D000735:Androstenedione / Q000378:metabolism*; D002117:Calcitriol / Q000494:pharmacology*; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D004970:Estrone / Q000378:metabolism*; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D013268:Stimulation, Chemical
chemical_list: D004970:Estrone; D000735:Androstenedione; D003513:Cycloheximide; D002117:Calcitriol