FERNANDINO Juan Ignacio
congresos y reuniones científicas
Temperature influeces of aromatase and estrogen receptor mRNA expression during the critical period of sex determination/differentiation in pejerrey fish (Odontesthes bonariensis) brain
STROBL MAZZULLA, PABLO HERNAN; GUILGUR, GASTON LEONARDO; JUAN IGNACIO FERNANDINO; LEANDRO ANDRES MIRANDA; GUSTAVO MANUEL SOMOZA
Congreso; V Congresso da Associacao Ibérica de Endocrinología Comparada; 2005
Asociación Ibérica de Endocrinología Comparada
Water temperature has an important influence not only on gonadal sex differentiation, but also on the development of the central neuroendocrine system in pejerrey fish (Odolntesthes bonariensis). It is known that estrogens play an important role in the differentiation of the ovary in non-mammalian species. It is also known that estrogens are crucial in teleost brain differentiation and maturation. In this context, semi-quantitative RT-PCR method was used in order to investigate the effects oftemperatllre on the ontogenetic expression of brain aromatase enzyme (CYP 19A2) and estrogen-receptors (ERs) in the developing brain of pejerrey fish. Temperature-induced sex differentiation in pejclTey larvae (19°C all females and 28°C all males) was applied during 5 weeks and then kept at 24°C until the histological sex ratios could be determined. Every week 6 fish were sampled, and their head dissected heads were sampled and individually processed for semi-quantitative analysis. CYPl9A2 transcripts could be first detected on day 14 post-hatching (dph) at both temperatures. However, on days 14,21 and 28 dph CYPI9A2 expressiorl was higher at male-forming temperature, reaching a peak at 21 dph. ERa and pwere firstly detected on day 7 at both temperatures. On days 7 and 14 the ER~ expression was higher a female-fomling temperature, but at day 21 the expression reach a peak at maleforming temperature and was almost undetectable at female-forming temperature. After the day 21 CYPI9A2 and ERp transcripts show the same expression pattern at both temperatures, suggesting a correlation in their expression. On the other hand, ERa was clearly not related to temperature and a peak was detected at day 28 at both temp~~tures. Taking together these data suggest that both CYP 19A2 and ERp are temperature-dependent during the critical period of sex determination. Their timing and expression could then be related with the brain sex-differentiation and the concomitant gonadal differentiation.