Cloning of GTHs in Cichlasoma dimerus pituitary and brain: Effect on pituitary hormones release

PANDOLFI M; POZZI A; CANEPA M; VISSIO PG; MAGGESE MC; LOBO G

Mar del Plata, Argentina

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Investigacion en Bioquímica y Biología Molecular; 2007

Sociedad Argentina de Investigacion en Bioquímica y Biología Molecular

FSH and LH play key roles in vertebrate gametogenesis and steroidogenesis. They are mainly synthesized in the pituitary gland. While investigating the ontogeny  of FSH and LH cells in the cichlid fish C. dimerus by IHC, we unexpectedly found immunoreactive neurons in the preoptic area, sending their projections  through different brain areas and neurohypophysis. Western blot and IHC techniques applied to adult brain confirmed these findings. To further demonstrate the extra-pituitary expression of these hormones, we performed RT-PCR detecting sequences coding for FSH-ß and LH-ß subunits in C. dimerus pituitary and brain. The expression, of these transcripts in both organs was consistent with their peptide expression showing a high sequence homology when compared with other phylogenetically related fish. Pituitary explant were cultured for 2 days with different concentrations of LH or FSH. The culture media was analyzed by western blot. LH produced a dose-dependent increase in pituitary LH and SL release and an increase in FSH release. No effect was observed on GH. The effect6 on PRL was not consistent among treatments. FSH produced an inhibition in LH release, a dose-dependent increase FSH and SL release and no effect on PRL and GH release. This is the first work showing, in vertebrates, an effect of brain derived GtHs on different pituitary cells.