The Potential Role of Amh to Prevent Ectopic Female Development in Testicular Tissue of the Protandrous Black Porgy, Acanthopagrus schlegelii 1 Running Title: ECTOPIC FEMALE GROWTH IS ARRESTED BY Amh SIGNALING

In most vertebrates, hermaphroditism results in infertility. However, hermaphroditism occurs in 6 % of teleosts, which primarily undergo protogyny. Here, to elucidate the transient stage from gonochorism to hermaphroditism, juvenile black porgies as a model animal were fed a diet containing estradiol (E2) for 3-mo, followed by withdrawal of E2 treatment. The E2-terminated fish had ectopically-located oocytes in the regenerated testes. anti-mullerian hormone (amh) was strongly expressed in the Sertoli cells with type A spermatogonia and follicle cells with vitellogenic oocytes. Amh was robustly expressed in the ectopic oocytes-bordering region of regenerated testes and in testes with non-synchronous spermatogenesis. This Amh was released by Sertoli cells and aggregated in the area containing type A spermatogonia in the ectopic oocytes-bordering region. Our in vitro results show that exogenous recombinant Amh (rAmh) can inhibit type A spermatogonia proliferation in the testis, but not oogonia proliferation in the ovary. We suggest that Amh-arrested spermatogonia A may act as a boundary to block inter-cellular communication (i.e., prevent peptide factors released from female tissue to alter the sexual fate of type A spermatogonia) and further inhibit female growth. These results suggest that black porgy can prevent ectopic femal