The function of ENSG00000164404 (GDF9, growth differentiation factor 9) is as follows. Required for ovarian folliculogenesis. Promotes primordial follicle development. Stimulates granulosa cell proliferation. Promotes cell transition from G0/G1 to S and G2/M phases, through an increase of CCND1 and CCNE1 expression, and RB1 phosphorylation. It regulates STAR expression and cAMP-dependent progesterone release in granulosa and thecal cells. Attenuates the suppressive effects of activin A on STAR expression and progesterone production by increasing the expression of inhibin B. It suppresses FST and FSTL3 production in granulosa-lutein cells. {ECO:0000269|PubMed:12050262, ECO:0000269|PubMed:19366876, ECO:0000269|PubMed:20660033, ECO:0000269|PubMed:21632818, ECO:0000269|PubMed:21829661}.