Suzuki H, Yamamoto T, Kikuyama S, Uemura H
Department of Biology, Kanagawa Dental College, Yokosuka, Japan.
Gen Comp Endocrinol. 1997 Jul;107(1):12-22. doi: 10.1006/gcen.1997.6899.
Immunohistochemical and immunocytochemical techniques were employed to investigate the distribution of endothelin 3 (ET3)-like immunoreactivity in the pituitary of the bullfrog, Rana catesbeiana. ET3-immunoreactive (ET3-IR) cells were scattered all over the pars distalis of the female pituitary; however, only a few ET3-IR cells were observed in the male pituitary. ET3-IR cells were found to correspond to cells immunostained with monoclonal antibodies against the beta-subunit of bullfrog LH (fLH beta) or monoclonal antibodies against the beta-subunit of bullfrog FSH (fFSH beta) at the light microscopic level. However, we could not find ET3-IR cells which were immunoreactive for other pituitary hormones. So far, all ET3-IR cells showed both fLH beta and fFSH beta immunoreactivity. About 24% of the fLH beta-IR cells and about 33% of the fFSH beta-IR cells showed ET3-like immunoreactivity. Immunoelectron microscopic analysis using colloidal gold revealed the coexistence of ET3-like substance(s) and gonadotropins within the same granules. This study demonstrated the presence of ET3-like peptide(s) in bullfrog gonadotrophs, suggesting the possible participation of ET3 in regulating pituitary function as an autocrine and/or paracrine hormone.
采用免疫组织化学和免疫细胞化学技术研究了牛蛙（Rana catesbeiana）垂体中内皮素3（ET3）样免疫反应性的分布。ET3免疫反应性（ET3-IR）细胞散布在雌性垂体远侧部各处；然而，在雄性垂体中仅观察到少数ET3-IR细胞。在光学显微镜水平上，发现ET3-IR细胞与用抗牛蛙促黄体激素（fLHβ）β亚基的单克隆抗体或抗牛蛙促卵泡激素（fFSHβ）β亚基的单克隆抗体免疫染色的细胞相对应。然而，我们未发现对其他垂体激素有免疫反应性的ET3-IR细胞。到目前为止，所有ET3-IR细胞均显示出fLHβ和fFSHβ免疫反应性。约24%的fLHβ-IR细胞和约33%的fFSHβ-IR细胞显示出ET3样免疫反应性。使用胶体金的免疫电子显微镜分析揭示了同一颗粒内ET3样物质与促性腺激素的共存。本研究证明了牛蛙促性腺细胞中存在ET3样肽，提示ET3可能作为一种自分泌和/或旁分泌激素参与调节垂体功能。
