Reproduction and growth are under multifactorial control of neurohormones and peripheral hormones. This study investigated seasonally related effects of GnIH, GnRH, and T3 on the reproductive and growth axis in male goldfish at three stages of gonadal recrudescence. The effects of injection treatments with GnRH, GnIH and/or T3 were examined by measuring serum LH and GH levels, as well as peripheral transcript levels, using a factorial design. As expected, GnRH elevated serum LH and GH levels in a seasonally dependant manner, with maximal elevations of LH in late stages of gonadal recrudescence (Spring) and maximal increases in GH in the regressed gonadal stage (Summer). GnIH injection increased serum LH and GH levels only in fish at the regressed stage but exerted both stimulatory and inhibitory effects on GnRH-induced LH responses depending on season. T3 treatment mainly had stimulatory effects on circulating LH levels and inhibitory effects on serum GH concentrations. In the liver and testes, we observed seasonal differences in thyroid receptors, estrogen receptors, vitellogenin, follicle-stimulating hormone receptor, aromatase and IGF-I transcript levels that were tissue- and sex-specific. Generally, there were no clear correlation between circulating LH and GH levels and peripheral transcript levels, presumably due to time-related response and possible direct interaction of GnRH and GnIH at the level of liver and testis. The results support the hypothesis that GnRH and GnIH are important components of multifactorial mechanisms that work in concert with T3 to regulate reciprocal control of reproduction and growth in goldfish.

中文翻译：

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雄性金鱼生殖和生长轴的多因素控制：GnRH，GnIH和甲状腺激素的影响。

生殖和生长受神经激素和周围激素的多因素控制。这项研究调查了GnIH，GnRH和T3对雄性金鱼在性腺再发三个阶段的生殖和生长轴的季节相关影响。使用因子设计通过测量血清LH和GH水平以及外周转录水平来检查GnRH，GnIH和/或T3注射治疗的效果。正如预期的那样，GnRH以季节性依赖的方式升高血清LH和GH水平，在性腺复发的后期（春季）LH最大升高，而在性腺发育阶段（夏季）GH最大升高。GnIH注射仅在退化阶段增加鱼类的血清LH和GH水平，但根据季节对GnRH诱导的LH反应产生刺激和抑制作用。T3治疗主要对循环LH水平具有刺激作用，对血清GH浓度具有抑制作用。在肝脏和睾丸中，我们观察到了组织和性别特异性的甲状腺受体，雌激素受体，卵黄蛋白原，促卵泡激素受体，芳香化酶和IGF-I转录水平的季节性差异。通常，循环的LH和GH水平与外周转录水平之间没有明确的相关性，大概是由于时间相关的反应以及GnRH和GnIH在肝脏和睾丸水平的直接相互作用所致。