Stress as the trigger for temperature male sex determination in pejerrey. Effects of cortisol on the expression of amh and cyp19a1.

FERNANDINO, J.I.; HATTORI, R.S.; STRÜSSMANN, C.A.; SOMOZA, G.M.

Buenos Aires

Jornada; X Jornadas de la Sociedad Argentina de Biología; 2008

Recent studies in pejerrey provided evidences on the involvement of cortisol in the masculinization at high temperatures (29ºC, MPT) where 100% males were obtained. Furthermore the administration of cortisol to pejerrey larvae raised at ?sexually neutral? temperature (24ºC; ♀ 50%: 50% ♂; MixPT) induced a male-biased sex ratio. Then, in order to access if the increase of cortisol may have an effect on the testicular differentiation cascade, amh and cyp19a1 (gonadal aromatase) expression was quantified using Real Time PCR on total RNA extracted from larvae grown at MixPT fed with food supplemented with cortisol (50mg/kg food). The treatment produced changes in the amh and cyp19a1 expression similar to those found in males exposed to MPT. These changes suggested that cortisol have a key role in the testicular differentiation process triggered by high temperatures in this species.