Huang Y S, Schmitz M, Le Belle N, Chang C F, Quérat B, Dufour S
Laboratoire de Physiologie Générale et Compareé, Muséum National d'Histoire Naturelle, URA 90 CNRS, Paris, France.
Mol Cell Endocrinol. 1997 Aug 8;131(2):157-66. doi: 10.1016/s0303-7207(97)00100-7.
Primary cultures of juvenile eel (Anguilla anguilla) pituitary cells were used to study the direct effects of sex steroids on gonadotropin (GtH-II) cell content and release (radioimmunoassay) as well as on mRNAs levels for alpha and GtH-II beta-subunits (dot-blot). Testosterone stimulated GtH-II production in a dose- and time-dependent manner by selectively increasing mRNAs for GtH-II beta-subunit but not alpha-subunit. This positive effect was also induced by non-aromatizable androgens (androstanediol and dihydrotestosterone) but not by estradiol, indicating an androgen-specific effect in the eel. The androgen-specific stimulation of eel GtH-II beta appears closer to the regulation of mammalian follicle stimulating hormone-beta (FSHbeta) than that of salmonid GtH-II beta or mammalian luteinizing hormone-beta (LHbeta)-subunits. Comparison with previous in vivo experiments suggests multiple sites of action of sex steroids on the brain-pituitary gonadotropic axis for the positive feedback on GtH-II synthesis in this juvenile fish.
利用幼年鳗鱼（欧洲鳗鲡）垂体细胞的原代培养物，研究性类固醇对促性腺激素（促性腺激素-II，GtH-II）细胞含量和释放（放射免疫测定）以及α和GtH-IIβ亚基mRNA水平（斑点印迹）的直接影响。睾酮通过选择性增加GtH-IIβ亚基而非α亚基的mRNA，以剂量和时间依赖性方式刺激GtH-II的产生。这种积极作用也由不可芳香化的雄激素（雄烷二醇和双氢睾酮）诱导，但雌二醇不能诱导，表明在鳗鱼中存在雄激素特异性效应。鳗鱼GtH-IIβ的雄激素特异性刺激似乎比鲑鱼GtH-IIβ或哺乳动物促黄体生成素-β（LHβ）亚基更接近哺乳动物促卵泡激素-β（FSHβ）的调节。与之前的体内实验比较表明，性类固醇在该幼年鱼类的脑-垂体促性腺轴上对GtH-II合成的正反馈有多个作用位点。
