[Effect prolonged GABAergic activation on the pubertal development of female rats]

We evaluated, in immature female rats, the effect of the GABAergic system on the reproductive axis and on pubertal development. Initially, using a prolonged treatment with aminooxyacetic acid (AOAA), increasing hypothalamic GABA (p < 0.002), and decreasing GnRH and glutamate content (p < 0.05 and < 0.02). Treated rats showed diminished serum LH (p < 0.05) and estradiol (p < 0.005) levels. Vaginal opening occurred at 30.8 +/- 0.6 days in controls, and at 36.7 +/- 0.98 days in AOAA-treated rats. Acute treatment with AOAA resulted in a decreased GnRH and glutamate output, and in an increased taurine release from superfused hypothalamic fragments. This effect was mimicked by the GABA-A and GABA-B agonists. The activation of the GABAergic system during postnatal days 23-29 significantly restrains the hypothalamo-pituitary-ovaric axis and delays the onset of puberty. The existence of a physiological cross-talk between excitatory and inhibitory amino acid neurotransmitters regulating GnRH release during the onset of puberty is postulated.