促性腺激素抑制激素(GnIH)对于调节哺乳动物的繁殖和抑制小鼠的睾丸活动至关重要。本研究旨在探讨GnIH通过下丘脑-垂体-睾丸轴作用于小鼠精子发生和类固醇发生的机制。小鼠皮下注射不同剂量的GnIH(1μg/150μL,3μg/150μL,6μg/150μL,150μL生理盐水,每天两次)持续11天。随后,黄体生成素(LH),睾酮(T),测定外周血抑制素B(INHB)水平,以及GnRH合成相关基因(GnRH-1,Kiss-1,NPY)和促性腺激素合成相关基因(FSHβ,LHβ,分别检测下丘脑和垂体中的GnRH受体)。此外,类固醇生成相关基因/蛋白的表达(P450scc,StAR和3β-HSD)和精子发生相关蛋白/基因,包括LH受体(LHR),雄激素受体(AR),热休克因子-2(HSF-2)和INHB使用蛋白质印迹和q-PCR进行分析。结果表明,GnIH治疗可明显降低外周血中LH的浓度。进一步分析显示,GnIH治疗显著降低下丘脑中GnRHImRNA和Kiss-1mRNA的表达,和FSHβ的mRNA水平,LHβ,和垂体中的GnRHR基因。我们还观察到GnIH处理显著降低T水平和P450scc的表达,StAR,和睾丸中的3β-HSD蛋白。此外,GnIH治疗下调LHR,AR蛋白,和睾丸中的HSF-2基因。重要的是,GnIH处理后,INHB浓度和INHβbmRNA水平显着下降。此外,GnIH处理可诱导小鼠睾丸生殖细胞凋亡。总之,GnIH可能通过作用于小鼠下丘脑-垂体-睾丸轴而抑制精子发生和类固醇生成。
Gonadotropin inhibitory hormone (GnIH) is essential for regulating the reproduction of mammals and inhibiting testicular activities in mice. This study aimed to explore the mechanism of GnIH on spermatogenesis and steroidogenesis by acting through the hypothalamus-pituitary-testis axis of mice. Mice were subcutaneously injected with different doses of GnIH (1 μg/150 μL, 3 μg/150 μL, 6 μg/150 μL, 150 μL saline, twice daily) for 11 days. Subsequently, luteinizing hormone (LH), testosterone (T), and inhibin B (INH B) levels of peripheral blood were determined, and the expression of GnRH synthesis-related genes (GnRH-1, Kiss-1, NPY) and gonadotropin synthesis-related genes (FSH β, LH β, GnRH receptor) in the hypothalamus and pituitary gland were respectively detected. Additionally, the expression of steroidogenesis-related genes/proteins (P450scc, StAR and 3β-HSD) and spermatogenesis-related proteins/genes including LH receptor (LHR), androgen receptor (AR), heat shock factor-2 (HSF-2) and INH B were analyzed using western blot and q-PCR. Results showed that GnIH treatment significantly reduced the concentration of LH in the peripheral blood. Further analysis revealed that GnIH treatment markedly reduced the expression of GnRHImRNA and Kiss-1 mRNA in the hypothalamus, and mRNA levels of FSH β, LH β, and GnRHR genes in the pituitary. We also observed that GnIH treatment significantly decreased T levels and expression of the P450scc, StAR, and 3β-HSD proteins in the testis. Furthermore, GnIH treatment down-regulated LHR, AR proteins, and HSF-2 gene in the testis. Importantly, the INH B concentration of and INH βb mRNA levels significantly declined following GnIH treatment. Additionally, GnIH treatment may induce germ cell apoptosis in the testis of mice. In conclusion, GnIH may suppress spermatogenesis and steroidogenesis by acting through the hypothalamus-pituitary-testis axis in mice.