虎纹蛙促性腺激素释放激素分泌调节的离体研究(英文)

IN VITRO STUDIES ON GONADOTROPIN-RELEASING HORMONE SECRETION IN RANA RUGULOSA

利用离体静态孵育系统和放射免疫测定法 ,研究了性成熟的虎纹蛙雌蛙离体的视前 -下丘脑 -正中隆起 (P H ME)片段促性腺激素释放激素 (GnRH)的分泌调节。结果表明 :γ -氨基丁酸 (GABA)对成熟前期蛙离体P H ME片段的哺乳类GnRH (mGnRH)的释放有显著的刺激作用 ;随着GABA作用浓度的增加 ,刺激作用逐渐增强。 10 0 μmol/L的多巴胺 (DA)及 1μmol/L和 10 μmol/L的雌二醇 (E2 )则显著抑制鸡ⅡGnRH (cGnRH -Ⅱ )的释放。 10 μmol/L和 10 0 μmol/L的睾酮 (T)以及 10 μmol/L的E2 显著刺激冬眠期蛙P H ME片段mGnRH的释放。这些结果说明 ,GABA、DA及E2 和T对虎纹蛙GnRH的释放有直接的调节作用。

In vitro release of gonadotropin releasing hormone (GnRH) from the slices of the brain preoptic hypothalamus median eminence (P H ME) region of adult Rana rugulosa females was studied by using a static incubation system and raidoimmunoassay (RIA). γ aminobutyric acid (GABA) at 0 1～10 μmol/L (significantly) stimulated the release of mammalian GnRH (mGnRH) from the slices of P H ME of sexually pre mature frog, the stimulatory action was enhanced with the increasing concentrations of GABA, and was significant at 1 μmol/L or 10 μmol/L; 100 μmol/L dopamine (DA) and 1 μmol/L or 10 μmol/L estradiol (E 2) markedly inhibited the release of chicken Ⅱ GnRH (cGnRH Ⅱ). Both 10 μmol/L or 100 μmol/L testosterone (T) and 100 μmol/L E 2 significantly stimulated the release of mGnRH from the slices of P H ME of hibernating frog. These results demonstrate that GABA, DA, E 2 and T may have direct regulatory action on GnRH release from the brain of R.rugulosa.