Role of PPARγ and its gonadotrophic regulation in rat ovarian granulosa cells in vitro

The peroxisome proliferator-activated receptors (PPARs), including PPAR alpha, PPAR beta/delta, and PPAR gamma, are a family of transcription factors belonging to the steroid receptor superfamily. In rat ovary, PPAR gamma is mainly expressed in granulosa cells of developing follicles, implying a possible role of PPAR gamma in ovarian functions. In the present study, the role of PPAR gamma and its gonadotrophic regulation in granulosa cells collected from diethylstilbestrol-treated immature rats were studied. The results showed that PPAR gamma could inhibit proliferation and induce apoptosis in primarily cultured granulosa cells. PPAR gamma could also stimulate the biosynthesis of estradiol and progesterone after FSH pretreatment, and FSH could regulate the functions of PPAR gamma through PKA, ERK1/2, and p38 MAPK signaling pathways. These data suggested that PPAR gamma may be involved in follicular atresia and FSH-stimulated steroidogenesis during follicle development.