The role of FSH and TGF-β superfamily in follicle atresia.

Most of the mammalian follicles undergo a degenerative process called "follicle atresia". Apoptosis of granulosa cells is the main characteristic of follicle atresia. Follicle stimulating hormone (FSH) and the transforming growth factor ss (TGF-ss) superfamily have important regulatory functions in this process. FSH activates protein kinase A and cooperating with insulin receptor substrates, it promotes the PI3K/Akt pathway which weakens apoptosis. Both Smad or non-Smad signaling of the transforming growth factor ss superfamily seem to be related to follicle atresia, and the effect of several important family members on follicle atresia is concluded in this article. FSH and TGF-ss are likely to mutually influence each other and what we have already known about the possible underlying molecular mechanism is also discussed below.