Rapid Estrogen Signaling in Spermatogenesis

The role of estrogens in male reproductive tract physiology has for a long time been a subject of debate. A substantial advance in our understanding of the estrogen signaling in testicular cells occurred in the last years. The testis produces significant amounts of estrogenic hormones, via aromatase, and estrogen receptors (ER) α and β are selectively expressed in testicular cells. ERα and ERβ belong to the nuclear receptor family of transcription factors. In addition to the well established transcriptional effects, estrogens can mediate rapid signaling, triggered within seconds or minutes. These rapid effects can be mediated by ERs or by the recently discovered G protein-coupled estrogen receptor GPR30, involved in testicular cell proliferation, differentiation and apoptosis. This review summarizes the current knowledge on rodent spermatogenesis concerning the functions regulated by estrogens and mediated via both genomic and rapid mechanisms of action in testicular cells.