Abstract: The role of theca cells in the modulation of ovarian follicular function is reviewed. Theca cells are the endocrine cells associated with ovarian follicles that play an essential role in fertility by producing the androgen substrate required for ovarian estrogen biosynthesis. A distinguishing feature of theca cells may be their ability to initiate follicle growth on differentiation from cortical stromal cells，stimulate follicle growth by granulose cell mitosis through FSH-induced androgen receptor，and cause androgen-stimulated receptor formation of FSH. It should be emphasized that some apoptosis-counteracting growth facors of differing potency is secreted from theca cells to protect granulosa cells from undergoing apoptosis, suggestting an important role of theca cells in the follicular atresia. Therefore, theca cells have more significant role in follicular function than previously thought.

Key words: Theca cells, Androgens, Steroid, Ovary, Growth and development, Follicular atresia