Age- and sex-related changes in the components of the hepatic microsomal mixed function oxidase system in Sprague-Dawley rats.
1. A study of the sex- and age- (4 to 103 weeks) related changes in liver microsomal mixed-function oxidase components of Sprague-Dawley rats, showed that total cytochrome P-450 ranged from 12.0 to 34.0 nmol/g, peaking between weeks 26 and 39; males had higher levels than females at weeks 4 to 51. Cytochrome b5 ranged from 5.0 to 15.0 nmol/g with inconsistent age- and sex-related differences. 2. NADPH:cytochrome C reductase ranged from 2.6 to 4.8 mumol/min per g, with maximal activity at week 39; males had greater activity at weeks 12 to 78. NADH:cytochrome C reductase ranged from 5.2 to 26.9 mumol/min per g, peaking between weeks 51 and 78; females had greater activity at weeks 12 to 51. 3. This age- and sex-related pattern of changes in these components is specific to the Sprague-Dawley strain. There are slight but significant differences between sexes only in rats less than 1 year old. There was no significant correlation between rates of p-nitroanisole or aniline metabolism and cytochrome P-450 concentrations.
Chengelis
C P
CP
Department of Toxicology, G. D. Searle Research and Development, Skokie, IL 60077.
D000367:Age Factors; D000815:Aniline Hydroxylase / Q000378:metabolism; D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D003573:Cytochrome b Group / Q000378:metabolism; D015786:Cytochromes b5; D005260:Female; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D009245:NADH Dehydrogenase / Q000378:metabolism; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D009575:Nitroanisole O-Demethylase / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012737:Sex Factors
D003573:Cytochrome b Group; D015786:Cytochromes b5; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D009575:Nitroanisole O-Demethylase; D000815:Aniline Hydroxylase; D009251:NADPH-Ferrihemoprotein Reductase; D009245:NADH Dehydrogenase