Effects of pregnancy and protein-energy malnutrition on monooxygenase O-dealkylation activity in rat liver microsomes.
Xenobiotic metabolism is influenced by a variety of physiological and environmental factors including pregnancy and nutritional status of the individual. Pregnancy has generally been reported to cause a depression of hepatic monooxygenase activities. Low-protein diets and protein-energy malnutrition have also been associated with a reduced activity of monooxygenases in nonpregnant animals. We investigated the combined effects of pregnancy and protein-energy malnutrition on liver monooxygenase O-dealkylation activity. On pregnancy day 0 rats were assigned at random to a group fed ad libitum (well-nourished, WN) or to a malnourished group (MN) which received half of the WN food intake (12 g/day). WN and MN rats were killed on days 0 (nonpregnant), 11 or 20 of pregnancy and ethoxy- (EROD), methoxy- (MROD) and penthoxy- (PROD) resorufin O-dealkylation activities were measured in liver microsomes. Only minor changes in enzyme activities were observed on pregnancy day 11, but a clear-cut reduction of monooxygenase activities (pmol resorufin min-1 mg protein-1) was noted near term (day 0 vs 20, means +/- SD, Student t-test, P<0.05) in WN (EROD: 78.9 +/- 15.1 vs 54.6 +/- 10.2; MROD: 67.8 +/- 10.0 vs 40.9 +/- 7.2; PROD: 6.6 +/- 0. 9 vs 4.3 +/- 0.8) and in MN (EROD: 89.2 +/- 23.9 vs 46.9 +/- 15.0; MROD: 66.8 +/- 13.8 vs 27.9 +/- 4.4; PROD: 6.3 +/- 1.0 vs 4.1 +/- 0. 6) dams. On pregnancy day 20 MROD was lower in MN than in WN dams. Malnutrition did not increase the pregnancy-induced reduction of EROD and PROD activities. Thus, the present results suggest that the activities of liver monooxygenases are reduced in near-term pregnancy and that protein-energy malnutrition does not alter EROD or PROD in pregnant rats.
Kuriyama
S N
SN
Laboratório de Toxicologia Ambiental, Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil.
De-Oliveira
A C
AC
Fidalgo-Neto
A A
AA
Paumgartten
F J
FJ
D000704:Analysis of Variance; D000818:Animals; D001711:Biotransformation; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism*; D019362:Cytochrome P-450 CYP2B1 / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D005260:Female; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D009929:Organ Size; D010088:Oxidoreductases / Q000378:metabolism*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000378:metabolism*; D011502:Protein-Energy Malnutrition / Q000201:enzymology*; D051381:Rats; D017208:Rats, Wistar; D015430:Weight Gain; D015262:Xenobiotics / Q000378:metabolism
D015262:Xenobiotics; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; C076307:methoxyresorufin-O-demethylase; D019363:Cytochrome P-450 CYP1A1; D019362:Cytochrome P-450 CYP2B1