Endocrine Abstracts

Follistatin-like 3 (FSTL3) is a secreted glycoprotein known to act as an inhibitor of TGFβ ligands such as activin and myostatin. Like activin, FSTL3 is expressed strongly in the testis but the role FSTL3 plays in testis development and physiology is not clearly understood. Here we show that FSTL3 is a key regulator of testicular size and a promoter of age-dependent testicular regression. FSTL3 deletion in mice leads to the development of enlarged testes that show delayed...

The bioavailability of activin, GDF11, and myostatin, members of the TGFβ superfamily, is regulated by the soluble antagonists follistatin (FST) and follistatin like-3 (FSTL3). Activin influences tissue fate determination and organogenesis in embryos as well as organ homeostasis in adults while myostatin decreases muscle mass in adults and GDF11 regulates pancreatic β-cell differentiation. In addition, the FST gene produces three protein forms (FST288, FST303, and FS...