IBBEA   24401
INSTITUTO DE BIODIVERSIDAD Y BIOLOGIA EXPERIMENTAL Y APLICADA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Neuropeptide Y (NPY) increases gonadotropins (GtH) and growth hormone release and synthesis in cichlid fish Cichlasoma dimerus
Autor/es:
MARÍA P. DI YORIO; DANIELA I. PÉREZ SIRKIN; TOMAS H. DELGADIN; PAULA G. VISSIO
Lugar:
Olhão
Reunión:
Congreso; 10 th International Symposium on Reproductive Physiology of Fish; 2014
Resumen:
Introduction Reproduction and growth depend on feeding status. NPY is considered the most important orexigenic peptide, increasing before meal time and during fasting. In mammals, NPY modulates reproduction and growth acting through the hypothalamic-pituitary axis; however in teleosts few studies have been conducted. The aim of this study was to evaluate whether NPY modulates the expression and release of GtH and GH in C. dimerus. First, we studied possible morphological relationships between NPY fibers and these pituitary cells. Then we performed in vitro studies to evaluate the effect of NPY on GH, GtH synthesis/release. Finally, we analyzed variations of GH, GtH and NPY expression in brain and pituitaries of animals exposed to 1 week of fasting. Methods Morphological relationships: double label confocal inmunofluorescences were performed in hypothalamic-pituitary complex. In vitro studies: male?s and female?s pituitaries cultures were incubated with different concentrations of NPY (0, 2, 20, 200nM). We evaluated the expression of GtH and GH by Real time PCR (qPCR) in 4h culture, and the amount of protein released into the culture medium by western blot, in 24h culture. In vivo studies: animals of the same size were isolated and maintained in aquaria for two weeks (adaptation period) with a fix schedule of daily feeding time with commercial pellets at 1.5% of their body weight. Then fish were randomly assigned to feeding or fasting groups. After 1 week, variations in mRNA expression of GH, GtH and NPY were determined by qPCR in brains (telencephalon-POA; hypothalamus; and medium-posterior brain) and pituitaries. A two way ANOVA design was used to evaluate differences between treatments and sexes. Results and Discussion We detected contacts between NPY fibers and somatotropes and gonadotropes, indicating possible functional relationships. We observed an increase in GH release of male?s (2nM vs control (C),p