The critical granulosa cell complement: Lessons from the cyclin D2 knockout

Growth, ovulation, and luteinization of ovarian follicles is regulated by a number of distinct but interacting kinase cascades. Two of these kinase cascades are of paramount importance in regulating ovarian cell proliferation and differentiation. Cyclic AMP(cAMP)-dependent protein kinase (A-kinase) regulates growth and differentiation of ovarian cells by stimulating transcriptional activation of different genes, including those involved in the synthesis of mitogenic steroids (1–3). The myriad cell cycle-associated, cyclindependent protein kinases (cdks) control progression through the cell cycle (4–10). This chapter will summarize studies showing how these two cascades interact to regulate ovarian granulosa cell proliferation and ovulation (11, 12; Fig. 4.1).