Effects of luteinizing hormones on glucose-6-phosphate and 20-alpha-hydroxysteroid dehydrogenase activities in superovulated rat ovaries.

Abstract

Glucose-6-phosphate dehydrogenase and 20α-hydroxysteroid dehydrogenase activities were measured biochemically and localized histochemically in ovaries of immature rats during extensive follicular maturation and corpus luteum formation induced by pregnant mare's serum and human chorionic gonadotrophin. Ovarian enzyme activities and weights of ovaries and uteri were maximal 5 days after initiating treatment. Increases in both enzyme activities were related to the process of luteinization. Glucose-6-phosphate dehydrogenase activity was localized in ovarian theca and interstitial cells of control rats; however, 20α-hydroxysteroid dehydrogenase activity was not demonstrable in ovaries of these animals. During luteinization glucose-6-phosphate dehydrogenase activity was demonstrated in all cells of corpora lutea, while 20α-hydroxysteroid dehydrogenase was localized in discrete groups of cells appearing first at the periphery of, and later within, the corpora lutea. Subsequent administration of luteinizing hormone and human chorionic gonadotrophin beginning 9 days after the initiation of gonadotrophin priming resulted in large increases in both dehydrogenase activities. At this time both enzymes were distributed uniformly throughout all luteinized granulosa cells. The results are discussed in relation to the probable role the enzymes play in influencing the secretion of ovarian steroids during superovulation, the estrous cycle and pregnancy. (Endocrinology79: 352, 1966)