Activins in male reproduction

The activins are growth factors in the transforming growth factor-β (TGFβ) superfamily. They have both endocrine and paracrine roles that are central to male reproductive biology and health. This article gives a general overview of activin structure and signaling activity. Activin action within the pituitary is described in the context of the hypothalamic–pituitary–gonadal axis of the male. Activin intratesticular actions affecting cell fate and organ growth are identified, including distinctions between somatic and germline functions and developmentally regulated effects. Areas where dysregulated activin function may be of relevance to male reproductive pathologies are considered, including infertility, inflammation, and testicular cancer.