The gonadotropin‐releasing hormone—gonadotropin inhibitor (GnRH–GnIH) system in the hypothalamus of mammals is the key factor that controls the entire reproductive system. The aim of this study was to immunolocalize GnIH (RFRP‐3) in the hypothalamus during the estrous cycle and to study the effect of putrescine on the expression of GnRH‐I and GnIH through both in vivo and in vitro (GT1‐7 cells) approach and the circulatory levels of GnRH‐I, GnIH, and gonadotropins were also investigated. The study also aims in analyzing all the immunofluorescence images by measuring the relative pixel count of an image. This study showed the effect of putrescine on the morphology of ovary, uterus, and the expression of the steroidogenic acute regulatory protein in the ovary. This study showed GnIH expression was intense during the diestrus and moderate during proestrus and estrus, whereas mild staining during the metestrus. The study further showed that putrescine supplementation to adult female rats increased both GnRH‐I expression in the hypothalamus as well as the GnRH‐I levels in circulation. The study, for the first time, also showed that putrescine supplementation decreased the expression and release of GnIH. These effects of upregulating GnRH‐I expression and downregulating GnIH expression were confirmed by in vitro experiments using GT1‐7 cells. Putrescine supplementation also increased the gonadotropin levels in the serum. To summarize, putrescine can regulate the hypothalamic–pituitary–gonadal axis by increasing the GnRH‐I, luteinizing hormone, and follicle‐stimulating hormone levels and suppressing GnIH levels. This is the first report showing the simultaneous effects of putrescine on the regulation of both GnRH‐I and GnIH in the hypothalamus.

中文翻译：

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腐胺在成年雌性大鼠和GT1-7神经元细胞系中对下丘脑GnRH-GnIH系统的调节。

哺乳动物下丘脑中的促性腺激素释放激素—促性腺激素抑制剂（GnRH–GnIH）系统是控制整个生殖系统的关键因素。这项研究的目的是在动情周期中将GnIH（RFRP-3）免疫定位在下丘脑中，并研究腐胺通过体内和体外（GT1-7细胞）对GnRH-1和GnIH表达的影响还研究了GnRH-1，GnIH和促性腺激素的循环水平。该研究还旨在通过测量图像的相对像素数来分析所有免疫荧光图像。这项研究显示了腐胺对卵巢，子宫形态以及卵巢中类固醇生成的急性调节蛋白表达的影响。这项研究表明，GnIH表达在发情期强烈，在发情期和发情期中等，而在发烧期则轻度染色。研究进一步表明，对成年雌性大鼠补充腐胺会增加下丘脑中GnRH-I的表达以及循环中GnRH-I的水平。这项研究首次显示，补充腐胺会降低GnIH的表达和释放。使用GT1-7细胞进行的体外实验证实了上调GnRH-I表达和下调GnIH表达的这些作用。补充腐胺还增加了血清中的促性腺激素水平。总之，腐胺可以通过增加GnRH-I，促黄体生成素，调节下丘脑-垂体-性腺轴，以及刺激卵泡的激素水平和抑制GnIH水平。这是第一份报告，显示腐胺同时对下丘脑中GnRH-1和GnIH的调节作用。