Primary cultures of chick kidney cells convert 25-hydroxycholecalciferol into more-polar metabolites. Cells from vitamin D-deficient chicks have high 25-hydroxycholecalciferol 1 alpha-hydroxylase (1 alpha-hydroxylase) activity, but no 25-hydroxycholecalciferol 24-hydroxylase (24-hydroxylase) activity. Physiological concentrations of 1,25-dihydroxycholeclaciferol suppress 1 alpha-hydroxylase and induce 24-hydroxylase activity. The inhibition of 1 alpha-hydroxylase preceded the induction of 24-hydroxylase. In contrast, oestradiol-17 beta had no effect on the activity of either hydroxylase under a variety of experimental conditions. These results clearly demonstrate that 1,25-dihydroxycholecalciferol, but not oestrogen, acts directly on the kidney cells to regulate the metabolism of 25-hydroxycholecalciferol.
Effect of oestrogen and 1,25-dihydroxycholecalciferol on 25-hydroxycholecalciferol metabolism in primary chick kidney-cell cultures
- Views Icon Views
- Share Icon Share
E Spanos, D I Barrett, K T Chong, I MacIntyre; Effect of oestrogen and 1,25-dihydroxycholecalciferol on 25-hydroxycholecalciferol metabolism in primary chick kidney-cell cultures. Biochem J 15 July 1978; 174 (1): 231–236. doi: https://doi.org/10.1042/bj1740231
Download citation file: