US EPA

5146866 

Journal Article 

Metabolism of xenobiotics in undernourished rats: Regulation by dietary energy and protein levels 

Kalamegham, R; Naidu, NA; Krishnaswamy, K 

1981 

1 

Nutrition Reports International
ISSN: 0029-6635 

24 

4 

755-768 

English 

HEEP COPYRIGHT: BIOL ABS. Oxidative metabolism of foreign compounds by liver microsomal preparations was investigated in male albino rats subjected to varying grades of undernutrition. The effect of undernutrition on the activities of microsomal monooxygenases varied depending on the degree of undernutrition and the type of substrate being investigated. Thus, in vitro metabolism of aminopyrine (a type I drug) and hepatic content of cytochrome P-450 were both significantly depressed in animals with weight deficits of 40% (compared to ad lib fed controls), whereas metabolism of benzo(a)pyrene, a carcinogenic polycyclic hydrocarbon, as studied by benzo(a)pyrene hydroxylase activity, was impaired significantly in only more severe forms of undernutrition (weight deficits of 60%). Severe protein deficiency (5% casein) also significantly impaired aminopyrine demethylase and benzo(a)pyrene hydroxylase activities and cytochrome P-450 levels but marginal protein diet (10% casein) did not. The effects of protein and energy inadequacies in regulating the microsomal monooxygenases in malnutrition were studied by multiple regression analysis. The levels of these 2 nutritional factors together explained as much as 47-62% of the variance in the monooxygenase activities.