title: Growth hormone and drug metabolism. Acute effects on microsomal mixed-function oxidase activities in rat liver.
abstract: Adult male rats were subjected either to sham operation or to hypophysectomy and adrenalectomy and maintained for a total of 10 days before treatment with growth hormone. Results of the early effects of growth hormone on the activities of the mixed-function oxidases in rat liver over a 96h period after growth-hormone treatment are presented. 2. Hypophysectomy and adrenalectomy result in decreased body and liver weight and decreased drug metabolism (mixed-function oxidases). Concentrations of electron-transport-system components are also decreased. 3. In the hypophysectomized/adrenalectomized rats, growth hormone decreases the activities of the liver mixed-function oxidases and the cytochrome P-450 and cytochrome c reductases, as well as decreasing the concentration of cytochrome P-450 compared with that of control rats. Similar but less dramatic results are obtained with sham-operated rats. 4. It is concluded that whereas growth hormone enhances liver growth, including induction of many enzyme activities, it results in a decrease in mixed-function oxidase activity. Apparently, mixed-function oxidase activity decreases in liver when growth (mitogenesis) increases.
mesh_terms: D000315:Adrenalectomy; D000814:Aniline Compounds / Q000378:metabolism; D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D003579:Cytochrome Reductases / Q000378:metabolism; D004227:Dithionite; D013006:Growth Hormone / Q000494:pharmacology*; D006591:Hexobarbital / Q000378:metabolism; D007016:Hypophysectomy; D008099:Liver / Q000254:growth & development / Q000378:metabolism; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism*; D051381:Rats
chemical_list: D000814:Aniline Compounds; D004227:Dithionite; D013006:Growth Hormone; D003577:Cytochrome P-450 Enzyme System; D006591:Hexobarbital; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D003579:Cytochrome Reductases