Ovarian follicle populations of the rat express TGF-β signalling pathways

The transforming growth factor-β (TGF-β) superfamily comprises more than 40 members, classified on the basis of structural similarity. These factors elicit a diverse range of cellular responses in insects, nematodes and vertebrates, via serine/threonine kinase receptors and intracellular Smad proteins, which when activated mediate gene transcription. Some members of the superfamily, notably activin, TGF-β, GDF-9 and the bone morphogenetic proteins have been shown to influence ovarian function. Despite these actions, TGF-β superfamily signalling pathways and specifically those within follicle population subtypes, have been poorly characterised in the ovary. We have shown that the ovary contains type I and II receptors and Smads, which enable it to transduce signals in response to TGF-β superfamily members. It remains to be established however, as to which follicle subtypes these pathways are active in.