Purity >95% as determined by SDS-PAGE. Activin A is a member of the transforming growth factor beta (TGF-?) family of proteins and functions to stimulate follicle-stimulating hormone (FSH) secretion. Activins are produced in many tissue types including the skin, gonads, lungs, and pituitary gland. Activins interact with receptor type I and type II serine/threonine protein kinases, to activate SMAD signaling and regulate diverse cellular functions, such as cell proliferation, differentiation, wound healing, apoptosis, and metabolism. Activin A is a homodimer comprised of two activin ?A chains. Cleavage of the N-terminal propeptide renders the activin protein biologically active. Mouse activin A shares 100% amino acid sequence identity with human, rat, porcine, bovine, and feline activin A proteins.