title: Tissue and subcellular distributions of cholecalciferol 25-hydroxylase: cytochrome P-450D25-linked monooxygenase system.
abstract: Cholecalciferol (vitamin D3) 25-hydroxylase activity and its tissue and subcellular distributions were studied using rabbit, rat, bovine, chick, duck, guinea-pig and yellowtail. Vitamin D3 25-hydroxylase was found not only rabbit and bovine livers, kidneys and intestines, but also in lungs, pituitary glands, adrenocortices, ovaries, adipose tissues, blood vessels, brains and testes. Subcellular fractions of rabbit livers were examined for the presence of this activity and it was detected in the nuclear membranes, smooth and rough endoplasmic reticula, Golgi membranes and mitochondrial membranes. The activity in microsomes was induced by sodium phenobarbital, but not by beta-naphthoflavone and 3-methylcholanthrene, and was inhibited by isocyanide and metyrapone as inhibitor of cytochrome P-450.
mesh_terms: D000818:Animals; D002417:Cattle; D002645:Chickens; D053493:Cholestanetriol 26-Monooxygenase; D003577:Cytochrome P-450 Enzyme System / Q000302:isolation & purification*; D004372:Ducks; D006168:Guinea Pigs; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008168:Lung / Q000201:enzymology; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology; D008930:Mitochondria, Liver / Q000201:enzymology; D009928:Organ Specificity; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity; D013250:Steroid Hydroxylases / Q000302:isolation & purification*; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D053493:Cholestanetriol 26-Monooxygenase