The Involvement of Granulosa Cells in the Regulation by Gonadotropins of Cyp17a1 in Theca Cells

BACKGROUND/AIM: Theca cells produce androgen by 17α-hydroxylase-17,20-lyase encoded by Cyp17a1, and conversion of androgen to estrogen in granulosa cells is regulated by gonadotropins. Women with polycystic ovarian syndrome (PCOS) exhibit elevated levels of androgens due to high Cyp17a1 expression and alterations in gene expression in granulosa cells. The aim of this study was to examine the interaction between theca and granulosa cells in PCOS-model mice. MATERIALS AND METHODS: To produce PCOS-model mice, neonatal mice were injected with 1 μg TP for 3 days from the day of birth. Gonadotropins were injected according to the superovulation protocol to 3-month-old control mice and PCOS-model mice. Histological changes and expression of genes involved in steroidogenesis, ovulation and luteinization were investigated by immunohistochemistry and real-time RT-PCR, respectively. RESULTS: Pregnant mare serum gonadotropin (PMSG) induced the expression of genes involved in steroidogenesis in control prepubertal mice, whereas human chorionic gonadotropin (hCG) reduced Cyp17a1 expression and induced phospho-ERK1/2 in granulosa cells. Cyp17a1 was reduced in PMSG-primed PCOS-model mice regardless of hCG injection, and PMSG induced phosphorylation of ERK1/2 in granulosa cells. CONCLUSION: Phospho-ERK1/2 in granulosa cells can be correlated with reduced Cyp17a1 expression in theca cells, and the interaction between granulosa and theca cells may be impaired in PCOS-model mice.