title: Influence of temperature on basal and induced hepatic monooxygenase activity in rats of different ages.
abstract: The effect of temperature on the rates of ethylmorphine N-demethylation and ethoxycoumarin O-deethylation was studied with liver homogenates prepared from 1- to 120-day-old rats. Breaks at temperatures of 21.5-28.0 degrees C were observed in the Arrhenius plots of these reactions, differences being dependent mainly on age of the animals rather than on reaction type. No breaks could be demonstrated for ethylmorphine N-demethylation with liver homogenates of 10- and 120-day-old rats and for ethoxycoumarin O-deethylation in newborn and 120-day-old rats. In poikilothermic 3-, 10- and homothermic 30-day-old rats ethylmorphine N-demethylation rate was dependent on incubation temperature (7, 20 and 37 degrees C). The relative increase in N-demethylation rate after phenobarbital treatment was most marked in 30-day-old rats at an incubation temperature of 37 degrees C. In infantile rats the relative induction was highest at 7 degrees C.
mesh_terms: D015660:7-Alkoxycoumarin O-Dealkylase; D000367:Age Factors; D000818:Animals; D001571:Benzoflavones / Q000494:pharmacology; D005037:Ethylmorphine-N-Demethylase / Q000378:metabolism*; D005260:Female; D066298:In Vitro Techniques; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D010089:Oxidoreductases, N-Demethylating / Q000378:metabolism*; D010105:Oxygenases / Q000378:metabolism*; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013696:Temperature; D013816:Thermodynamics; D019324:beta-Naphthoflavone
chemical_list: D001571:Benzoflavones; D019324:beta-Naphthoflavone; D010105:Oxygenases; D015660:7-Alkoxycoumarin O-Dealkylase; D010089:Oxidoreductases, N-Demethylating; D005037:Ethylmorphine-N-Demethylase; D010634:Phenobarbital