Gonadotropins up-regulate the expression of enolase 2, but not enolase 1, in the rat ovary

摘要

It has been demonstrated that the glycolytic enzymes, enolase 1 (EN01) and enolase 2 (ENO2), are expressed in the rat ovary. In the present study, we found that mRNA levels of ovarian EN02 but not ENO1 in normal cycling adult female rats changed significantly during the estrous cycle: ovarian EN02 mRNA levels at metestrus were lower than those at estrus. Single injection of human CG (hCG) or equine CG (eCG) into immature (3 week old) rats up-regulated ovarian expression of EN02. hCG mainly increased ENO2 expression in oocytes and theca cells of preantral and antral follicles, and eCG did in theca cells of these follicles. In contrast, hCG and eCG did not affect the expression of EN01, which was mainly expressed in granulosa cells. These results suggest that endogenous gonadotropins up-regulate expression of EN02 in oocytes and theca cells of preantral and antral follicles, which would activate glycolysis in these cells. It is also suggested that the activated glycolysis is necessary for ovarian functions such as follicle growth and maturation, and hormone production.