title: Age-dependence of hepatic dimethylnitrosamine-demethylase activity in the rat.
abstract: The mixed-function oxidase which activates the carcinogen dimethylnitrosamine (DMN) was determined in the rat liver as a function of animal age. DMN-demethylase activity increased considerably at first to reach a maximum on day 29, and then substantially decreased to day 59; thereafter, enzyme activity remained essentially stable up to at least day 110. Pretreatment with 3-methylcholanthrene, which caused a pronounced decrease in this enzyme activity, did not affect the general shape of the age-dependence curve. The results suggest that rats between weaning and sexual maturity are more susceptible to the carcinogenic effects of pulse doses of DMN than are neonates or adult animals.
mesh_terms: D000375:Aging; D000818:Animals; D004128:Dimethylnitrosamine / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology; D008862:Microsomes, Liver / Q000201:enzymology; D009602:Nitrosamines / Q000378:metabolism*; D010089:Oxidoreductases, N-Demethylating / Q000378:metabolism*; D051381:Rats
chemical_list: D009602:Nitrosamines; D008748:Methylcholanthrene; D010089:Oxidoreductases, N-Demethylating; D004128:Dimethylnitrosamine