多巴胺、雌二醇及睾酮对虎纹蛙离体脑垂体促性腺激素分泌的影响(英文)

EFFECTS OF DOPAMINE,ESTRADIOL AND TESTOSTERONE ON GONADOTROPIN RELEASE FROM THE PITUITARY FRAGMENTS OF Rana rugulosa

为了解虎纹蛙促性腺激素分泌的调节机理 ,用离体静态培育系统和放射免疫测定法 ,研究了多巴胺 (DA)、雌二醇 (E2 )和睾酮 (T)对雌性虎纹蛙离体脑垂体薄片促黄体激素 (LH )和促卵泡激素 (FSH)分泌活动的影响。结果表明 :0 1～10 μmol/L的DA对成熟前期和冬眠期虎纹蛙离体脑垂体薄片的LH及FSH的释放都有抑制作用 ,并且随着DA浓度的增加 ,抑制作用逐渐增强。 1和 10μmol/L的E2 显著刺激成熟前期蛙LH的释放 ,而0 1～ 10 μmol/L的E2 显著抑制其FSH的释放 ;T对其FSH的释放无显著影响 ,但 10 μmol/L的T显著抑制其LH释放。 0 1～ 10 0 μmol/L的E2 或T对冬眠期蛙LH和FSH的释放均无显著影响。这些结果说明 ,多巴胺和性类固醇激素在脑垂体水平上对虎纹蛙LH和FSH的释放有直接的调节作用 ,而性类固醇激素的作用可能与性腺的发育阶段 (季节 )有关。

To understand the regulatory mechanisms of gonadotropin secretion in Rana rugulosa ,this study investigated the effects of dopamine (DA),estradiol (E 2) and testosterone (T) on the in vitro release of luteinizing hormone (LH) and follicle stimulating hormone (FSH) from the pituitary fragments of female Rana rugulosa using a static incubation system and radio immunoassay (RIA). The results indicated that DA at the concentration from 0 1?μmol/L to 10?μmol/L inhibited the release of LH and FSH from the pituitary fragments of sexually pre mature or hibernating individuals,and the inhibitory effects enhanced with increasing concentrations of DA. E 2 at 1?μmol/L and 10?μmol/L significantly stimulated the release of LH of sexually pre mature individuals,but inhibited their FSH release at 0 1?μmol/L to 10?μmol/L;T had no obvious effects on their FSH release,but significantly inhibited their LH release at 10?μmol/L. Neither E 2 nor T,at the concentration from 0 1?μmol/L to 100?μmol/L,had obvious effects on the release of LH and FSH of hibernating individuals. The data suggest that DA and sexual steroids may have direct regulatory actions on LH and FSH release at the pituitary level in Rana rugulosa ,and the action of sexual steroids may relate to the gonadal development stages (seasons).