State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, The Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou 510275, China.
Mol Cell Endocrinol. 2013 Feb 5;366(1):9-20. doi: 10.1016/j.mce.2012.11.001. Epub 2012 Nov 29.
Gonadotrophin-inhibitory hormone (GnIH) plays an important role in regulating of reproduction in teleosts. To clarify the mode of action of GnIH on the synthesis of gonadotropin releasing hormone (GnRH) and gonadotrophin (GtH), three GnIHR cDNAs were cloned from the goldfish brain. In situ hybridization results showed that GnIHRs were localized to the hypothalamus and pituitary. In the hypothalamus, GnIHRs were found in the NPP, NPO and NLT, whereas sGnRH neurons were reported to be located, and potentially regulated by GnIH. In the pituitary, only two GnIHRs were observed and they were localized to the PI instead of the adenohypophysis where GtH-expressing cells are localized, suggesting indirect regulation of GtH by GnIH. In vivo, intraperitoneal (i.p.) injections of synthetic goldfish GnIH-II peptide and GnIH-III peptide significantly decreased sGnRH and FSHβ mRNA levels. Only GnIH-II decreased LHβ mRNA levels significantly. In vitro, both GnIH-II and GnIH-III showed no effect on GtH synthesis, but an inhibition of GnRH-stimulated LHβ and FSHβ synthesis was observed when GnIH-III was applied to primary pituitary cells in culture. Thus, GnIH could contribute to the regulation of gonadotropin in the brain and pituitary in teleosts.
促性腺激素抑制激素（GnIH）在调节鱼类生殖方面发挥着重要作用。为了阐明 GnIH 对促性腺激素释放激素（GnRH）和促性腺激素（GtH）合成的作用方式，从金鱼脑中克隆了三个 GnIHR cDNA。原位杂交结果表明，GnIHRs 定位于下丘脑和垂体。在下丘脑中，GnIHRs 存在于 NPP、NPO 和 NLT 中，而 sGnRH 神经元被报道存在于这些部位，并可能受到 GnIH 的调节。在垂体中，只观察到两种 GnIHRs，它们定位于 PI，而不是 GtH 表达细胞所在的腺垂体，提示 GnIH 对 GtH 的间接调节。在体内，腹腔内（i.p.）注射合成的金鱼 GnIH-II 肽和 GnIH-III 肽显著降低了 sGnRH 和 FSHβ mRNA 水平。只有 GnIH-II 显著降低了 LHβ mRNA 水平。在体外，GnIH-II 和 GnIH-III 对 GtH 合成均无影响，但当 GnIH-III 应用于原代培养的垂体细胞时，观察到 GnRH 刺激的 LHβ 和 FSHβ 合成受到抑制。因此，GnIH 可能有助于调节鱼类脑垂体中的促性腺激素。
