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...