title: Rates of progesterone oxidation by rabbit liver microsomes before and after phenobarbitone treatment.
abstract: Liver sections, removed from outbred NZW rabbits under anesthesia, were used to determine the rates of progesterone oxidation prior to assessment of the effects of phenobarbitone(PB)-treatment. Progesterone 21-hydroxylase exhibited the same high affinity, low Km kinetics before and after PB-treatment, whereas the Vmax was significantly reduced. PB-treatment did not affect progesterone 21-hydroxylation by the adrenal microsomes of two groups of PB-treated and untreated rabbits. 21-Hydroxylase activity was detected for the first time with spleen microsomes but the majority of spleens examined lacked activity. 6 beta-Hydroxylation by control liver microsomes showed consistently low affinity, high Km-values and was inhibited to a lesser, inconsistent degree than 21-hydroxylation by PB-treatment.
mesh_terms: D000818:Animals; D066298:In Vitro Techniques; D007700:Kinetics; D008862:Microsomes, Liver / Q000201:enzymology / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D010634:Phenobarbital / Q000494:pharmacology*; D011374:Progesterone / Q000378:metabolism*; D011817:Rabbits; D013255:Steroid 21-Hydroxylase / Q000378:metabolism
chemical_list: D011374:Progesterone; D013255:Steroid 21-Hydroxylase; D010634:Phenobarbital