title: The effects of phenobarbitone on urinary 6 beta-hydroxycortisol excretion and hepatic enzyme activity in the guinea-pig.
abstract: Urinary 6 beta-hydroxycortisol is a useful, non-invasive index of microsomal mixed-function oxidase activity in man (review: [1]). Administration of phenobarbitone (40 mg/kg/day) for 4 days to male guinea-pigs, produced significant increases in hepatic microsomal cytochrome P-450 content and cytochrome P-450 reductase activity but did not increase 6 beta-hydroxycortisol excretion. The lack of relationship between urinary 5 beta-OHC excretion and microsomal mixed-function oxidase activity in the guinea-pig may be accounted for by the finding that 6 beta-hydroxycortisol itself undergoes extensive and variable metabolism in the guinea-pig.
mesh_terms: D000305:Adrenal Cortex Hormones / Q000652:urine; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D003579:Cytochrome Reductases / Q000378:metabolism*; D006168:Guinea Pigs; D006854:Hydrocortisone / Q000031:analogs & derivatives* / Q000652:urine; D008099:Liver / Q000187:drug effects; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D009245:NADH Dehydrogenase / Q000378:metabolism*; D009929:Organ Size / Q000187:drug effects; D010634:Phenobarbital / Q000494:pharmacology*
chemical_list: D000305:Adrenal Cortex Hormones; C001380:6 beta-hydroxycortisol; D003577:Cytochrome P-450 Enzyme System; D003579:Cytochrome Reductases; D009245:NADH Dehydrogenase; D006854:Hydrocortisone; D010634:Phenobarbital