几种神经内分泌因子对鲤促性腺激素释放激素(GnRH)释放的调节作用:离体研究

THE REGULATORY EFFECTS OF NEUROENDOCRINE FACTORS ON GONADOTROPIN-RELEASING HORMONE (GnRH) RELEASE FROM HYPOTHALAMUS AND PITUITARY OF JUVENILE AND ADULT COMMON CARP (CYPRINUS CARPIO) IN VITRO.

用离体静态培育系统进行的初步研究表明 ,在幼鲤 ,多巴胺 (DA)显著刺激下丘脑片段和脑垂体碎片释放GnRH ,并且是剂量依存的 ;促甲状腺素释放激素 (TRH)和γ -氨基酸丁酸 (GABA)对GnRH的释放没有影响。在成鲤 ,DA抑制下丘脑片段和脑垂体碎片释放GnRH ,而TRH和GABA刺激GnRH的释放 ;DA对GABA刺激的GnRH释放也具有抑制作用 ;TRH和GABA的协同作用对下丘脑和脑垂体GnRH释放活动的影响明显低于TRH和GABA的单独作用 ,表明TRH和GABA之间可能存在着某种GnRH释放的相互消竭作用。

In juvenile fish, DA significantly stimulates GnRH release from hypothalamus slices and pituitary fragments in a dose-response relation but TRH and GABA have no effects. In yearling sexually regressed fish, DA significantly inhibits GnRH release from hypothalamus slices and pituitary fragments in a dose-response relation, whereas TRH and GABA stimulate GnRH release. DA also inhibits GABA-stimulated GnRH release. When TRH in combination with GABA, the GnRH release from hypothalamus slices and pituitary fagments is much less than that of TRH and GABA alone, both in juvenile and yearling common carp. This result implies that there may exist an inter-inhibitory action on GnRH release between TRH and GABA.