Expression of AMH, SF1, and SOX9 in gonads of genetic female chickens during sex reversal induced by an aromatase inhibitor

Aromatase inhibitors administered prior to histological signs of gonadal se x differentiation can induce sex reversal of genetic female chickens. Under the effects of Fadrozole (CGS 16949A), a nonsteroidal aromatase inhibitor, the right gonad generally becomes a testis, and the left gonad a testis,or an ovotestis. We have compared the expression pattern of the genes encodin g AMH (the anti-Mullerian hormone), SF1 (steroidogenic factor 1), and SOX9 (a transcription factor related to SRY), in these sex-reversed gonads with that in control testes and ovaries, using in situ hybridization with ribopr obes on gonadal sections. In control males, the three genes are expressed i n Sertoli cells of testicular cords; however, only SOX9 is male specific, s ince as observed previously AMH and SF1 but not SOX9 are expressed in the c ontrol female gonads. In addition to testicular-like cords, sex-reversed go nads present many lacunae with a composite, thick and flat epithelium. We s how that during embryonic and postnatal development, AMH, SF1 and SOX9 are expressed in the epithelium of testicular-like cords and in the thickened p art but not in the flattened part of the epithelium of composite lacunae. A MH and SF1 but not SOX9 are expressed in follicular cells of ovotestes. Coe xpression of the three genes, of which SOX9 is a specific Sertoli-cell mark er, provides strong evidence for the transdifferentiation of ovarian into t esticular epithelium in gonads of female chickens treated with Fadrozole. ( C) 2001 Wiley-Liss, Inc.