IBBEA   24401
INSTITUTO DE BIODIVERSIDAD Y BIOLOGIA EXPERIMENTAL Y APLICADA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Brain aromatase expression levels and its relationship with agonistic behaviour in a Neotropical cichlid
Autor/es:
MARTÍN ROBERTO RAMALLO; GUSTAVO MANUEL SOMOZA; AGUSTINA BIRBA; LEONEL MORANDINI; MATÍAS PANDOLFI
Lugar:
Gothenburg
Reunión:
Simposio; 8TH INTERNATIONAL SYMPOSIUM ON FISH ENDOCRINOLOGY; 2016
Resumen:
Historically, there has been a supported notion that male to male aggressive behaviour is mainly regulated by androgens. However, in the past decades estradiol has emerged as a key element in the regulation of male reproductive and aggressive behaviour. The enzyme aromatase (CYP19A1) is the main element involved in estrogen biosynthesis through the conversion of C19 androgens to C18 estrogens. While a single cyp19a1 gene is present in non-teleost vertebrates, two copies are found in teleosts: cyp19a1a mostly expressed in the gonads, referred as gonadal aromatase, and cyp19a1b, mostly expressed in the brain, accordingly known as brain aromatase. In this work we aimed to analyze the variation in cyp19a1b expression in brain and pituitary of males of a highly social Neotropical cichlid, Cichlasoma dimerus, and its relationship with inter-individual variability in agonistic behaviour. We first began by characterizing C. dimerus specific cyp19a1b mRNA, and predicted amino acid sequence, and found a high degree of conservation when compared to other teleost brain aromatases, and its tissue expression pattern. Using an antibody raised against a conserved region of teleost aromatases, we studied CYP19A1B location within C. dimerus brain. Immunoreactivity was solely observed at putative radial glial cells of the forebrain, lining the walls of the ventricles, at the dorsal and ventral telencephalon, with the highest numbers of immunoreactive cells found at the preoptic area and hypothalamus. We then studied the relative expression levels of cyp19a1b by Real Time PCR in the brain and pituitary of males of different social status (territorial vs. non-territorial males), and its relationship with an index of agonistic behaviour. We found that even though, brain aromatase expression in whole forebrain and pituitary samples did not differ between types of males, pituitary cyp19a1b expression levels correlated with the index of agonistic behaviour (r=0.86, p=0.007), with a higher frequency of aggressive behaviour associated to a greater aromatase expression. This indicates an effect of the social environment on pituitary cyp19a1b expression, which might, in turn, result in the regulation of social behaviour by local estrogen synthesis.