查看文章

Oocytes regulate follicle growth by secreting paracrine growth factors that act on neighbouring granulosa cells (GCs). Those factors identified to date are mainly members of the transforming growth factor-β (TGFβ) superfamily, but little is known about which specific receptor/signalling system(s) they employ. This study was conducted to determine the requisite pathways utilised by oocytes to promote GC proliferation. We used an established oocyte-secreted mitogen bioassay, where denuded mouse oocytes are co-cultured with mural GCs. Oocytes, growth differentiation factor-9 (GDF9), TGFβ1 and activin-A all promoted GC DNA synthesis, but bone-morphogenetic protein 6 (BMP6) did not. Subsequently, we tested the capacity of various TGFβ superfamily receptor ectodomains (ECD) to neutralise oocyte- or specific growth factor-stimulated GC proliferation. The BMP type-II receptor (BMPR-II) ECD antagonised …