Effect of chronic exposure of pregnant rats to malathion and/or estrogen and/or progesterone on xenobiotic metabolizing enzymes
1994
Mathews, M.S. | Devi, K.S.
Pregnancy as well as exogenous administration of steroid hormones alters drug metabolizing enzymes, which could result in a change in the toxicity of malathion. The present study investigated the effect of exogenous estrogen and/or progesterone on malathion toxicity in pregnant rats and their 21-day-old pups. The activity of acetylcholinesterase in brain was taken as an index of malathion toxicity. Coadministration of estrogen plus malathion potentiated the malathion-induced toxicity while progesterone plus malathion at low dose decreased the toxicity, as evidenced by the changes in acetylcholinesterase activity in brain. The higher level of cytochrome P450 observed in estrogen plus malathion-administered rats might have stimulated the increased conversion of malathion to more potent malaoxon and also by blocking the glutathione S-transferase- and carboxylesterase-related detoxication process, resulting in increased malathion toxicity. However, coadministration of progesterone and malathion offered some degree of protection by stimulating the hepatic glutathione S-transferase- and carboxylesterase-mediated detoxication of malathion.
显示更多 [+] 显示较少 [-]