Epoxide-metabolizing enzyme activities and cytochrome P-450 content of rat ovaries during pregnancy

Abstract

Glutathione S -transferase activity was determined in 176,000 g supernatant fraction of ovaries, adrenals, and liver and in the serum of virgin, pregnant, lactating, and post-lactating female rats. A 90% increase in glutathione S -transferase specific activity was observed in the ovaries of pregnant rats whereas activity in the other tissues was not affected by pregnancy. The increase in ovarian glutathione S -transferase activity was not a function of the estrous cycle of the rat. The activity reached a maximum in midpregnancy and then remained constant until late pregnancy. The specific content of cytochromes P-450 and b 5 in microsomes prepared from rat ovaries was induced 3.7- to 4.7-fold during mid- and late pregnancy. No concomitant changes occurred in mitochondrial cytochrome P-450 concentrations. Microsomal aryl hydrocarbon hydroxylase and epoxide hydrase activities of ovaries from pregnant rats were not affected.