FERNANDINO Juan Ignacio
congresos y reuniones científicas
Sexually dimorphic- and estrogen-dependent expression of müllerian inhibiting substance during pejerry gonadal development.
JUAN IGNACIO FERNANDINO; HATTORI, R.S.; STÜSSMANN, C.A.; MANUEL SOMOZA, GUSTAVO
Simposio; 6th International Symposium on Fish Endocrinology; 2008
The Müllerian inhibiting substance (MIS) is a glycoprotein belonging to the TGF-β family of growth and differentiation factors. MIS is responsible for the regression of the Müllerian ducts in the mammalian male fetus, controls the development of the genital tract and may also influence Leydig cell function. Although teleost fish do not have Müllerian ducts, sexually dimorphic expression of MIS is evident during gonadal differentiation. In pejerrey, a fish with strong temperature-dependent sex determination, the proportion of males changes gradually from 0% at 19°C to 100% at 29°C. Pejerrey larvae were incubated at 17°C, 25°C and 29°C and the expression of MIS was determined by real-time SybrGreen-based PCR during an 8 week period following hatching. MIS displayed a significantly higher expression on week 5 at the male promoting temperature (29ºC). At the intermediate temperature (25°C), 55,2% of females were produced and MIS showed a bimodal pattern of expression, with high levels in half of the larvae and low levels in the remaining half. Larvae with high MIS expression also had high dmrt1 and low gonadal aromatase (cyp19A1) mRNA levels. Pejerrey larvae reared at 25°C and treated with estradiol had a female-like reduction in MIS. In contrast, larvae reared at 25°C and treated with an aromatase inhibitor (Fadrozole) displayed a male-like increase in MIS expression. These results show that MIS play an important role in testis differentiation in this species.