Follistatin/activin-binding protein.

ABSTRACT

Follistatin, or follicle-stimulating hormone (FSH) suppressing protein, is a protein isolated from side fractions in the purification of inhibin and activin, which shares with inhibin the property of suppressing the secretion of FSH from the pituitary gonadotroph. This protein is structurally distinct from inhibin. Recent observations that follistatin is an activin-binding protein suggest that it may have a much wider biologic role, given the variety of systems in which activin has been shown to act.