CONICET | Buscador de Institutos y Recursos Humanos

EFFECTS OF A GABAB ANTAGONIST ON OVARIAN AROMATASE, ESTROGEN RECEPTOR ALPHA AND BETA EXPRESSION N NEONATAL MICEBizzozzero M, Di Giorgio N, Tabares F, Libertun C and Lux-Lantos V. Instituto de Biología y Medicina Experimental (IBYME-CONICET, Buenos Aires, Argentina). We have previously shown that neonatal GABAB1KO female mice have decreased Kiss1 expression in the arcuate nucleus (ARC). In addition, the administration of a GABAB antagonist (CGP55845) to neonatal BALB/C mice significantly decreased ARC Kiss1 expression in both sexes. This suggests that a GABAB input can modulate Kiss1 expression in specific nuclei in neonates, at the time when neuronal connections are being established. The hypothalamic estrogenic system was not involved in this regulation as aromatase, estrogen receptor alpha (ERα) or estrogen receptor beta (ERβ) expression were not affected by this treatment. Nevertheless, we found that ovarian and testicular E2 contents were significantly increased in CGP-treated mice. Therefore, we cannot discard the possible participation of gonadal E2 in the modulation of ARC Kiss1 expression. Here we determined whether aromatase, ERα and ERβ expression are altered by this treatment in the ovary, justifying the increase in estradiol content.Female neonatal Balb/c mice were injected with CGP55845 (1 mg/kg, sc) or saline as control from postnatal day 2 (PND2) to PND6±1, three times/day (8AM, 1PM, 6PM). Mice were sacrificed at 3PM (after two injections on the last day). One ovary was collected to determine aromatase and ER expression by qPCR whereas the other one was used to analyze the effects of this increase of estradiol on ovarian morphology. Real-time PCR determined that aromatase expression was significantly increased by CGP55845 treatment in the neonatal ovaries (CTRL:0,97±0,32;CGP:2,5±0,55: CGP≠CTRL: p