Follistatin 315 Description: Follistatin 315 FST is a single chain gonadal protein that specifically inhibits follicle stimulating hormone release. The single FST gene encodes two isoforms Follistatin 317 and Follistatin 315 containing 317 and 315 amino acids respectively, resulting from alternative splicing of the precursor mRNA. In addition to being a natural antagonist, follistatin can inhibit the activity of other …