title: Stimulation of 25-hydroxyvitamin D3-1alpha-hydroxylase by phosphate depletion.
abstract: The ability of low phosphorus diets to stimulate the activity of the 25-hydroxyvitamin D3-1alpha-hydroxylase was tested in the chick. Feeding low phosphorus diets for 2 weeks resulted in a marked increase in enzyme activity relative to chicks fed a normal phosphorus diet. Stimulation of the 25-hydroxyvitamin D3-1alpha-hydroxylase activity by low phosphorus diets, however, was not as great as that observed with a low calcium diet. The low phosphorus and low calcium diets probably results from increased 1,25-dihydroxyvitamin D3 synthesis, whereas the stimulation by phosphate deprivation is only partly the result of increased 1,25-dihydroxyvitamin D3 production.
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002645:Chickens; D004032:Diet; D007413:Intestinal Mucosa / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008297:Male; D010710:Phosphates / Q000172:deficiency* / Q000378:metabolism; D013250:Steroid Hydroxylases / Q000378:metabolism*
chemical_list: D010710:Phosphates; D013250:Steroid Hydroxylases; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; D002118:Calcium