Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta, T2N 1N4, Canada.
Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta, T2N 1N4, Canada; Department of Morphology, Reproductive and Molecular Biology Group, São Paulo State University, Botucatu, São Paulo, Brazil.
Mol Cell Endocrinol. 2021 Jan 15;520:111087. doi: 10.1016/j.mce.2020.111087. Epub 2020 Nov 27.
Gonadotropin-inhibitory hormone (Gnih) is known to play a role in the regulation of reproduction in vertebrates by influencing gonadotropin release and synthesis. While the endocrine actions of Gnih have been identified in several species, its paracrine/autocrine effects in the control of spermatogenesis are less defined. We have used ex vivo culture of zebrafish testis to investigate the role of gonadal zebrafish Gnih (zGnih) in the regulation of the spermatogenic process. We used FACScan cell cycle analysis, morphometric quantifications, BrdU incorporation and caspase-3 activity assays as well as measuring 11-Ketotestosterone (11-KT) level in the culture media. FACScan analysis and morphometric quantification results demonstrated direct action of zGnih on basal and gonadotropin (Lh and Fsh)-induced spermatogenesis. Treatment with zGnih (10 nM) significantly decreased the number of G0/G1 cells after 7-days of culture while no significant changes were found in the proportion area of spermatogonia cell types. Investigation of DNA synthesis using BrdU (5-Bromo-2'-Deoxyuridine) labeling showed that treatment with zGnih (10 nM) significantly decreased proliferative activity of type A spermatogonia, while increased the mitotic activity of type B spermatogonia. We also showed that treatment with zGnih (100 nM) completely eliminated 11-KT release induced by 100 ng/ml Fsh. Treatment with zGnih (10 and 100 nM) also inhibited both hCG and Fsh-induced spermatogenesis. These results, plus our previous findings, demonstrate that zGnih produced locally in the testis is a component of a complex multifactorial system that regulates testicular function in zebrafish.
促性腺激素抑制激素（Gnih）被认为通过影响促性腺激素的释放和合成在脊椎动物的生殖调控中发挥作用。虽然已经在几种物种中确定了 Gnih 的内分泌作用，但它在控制精子发生中的旁分泌/自分泌作用还不太明确。我们使用斑马鱼睾丸的离体培养来研究性腺斑马鱼 Gnih（zGnih）在调节精子发生过程中的作用。我们使用 FACScan 细胞周期分析、形态计量定量、BrdU 掺入和半胱天冬酶-3 活性测定以及测量培养基中的 11-酮睾酮（11-KT）水平。FACScan 分析和形态计量定量结果表明 zGnih 对基础和促性腺激素（Lh 和 Fsh）诱导的精子发生有直接作用。用 zGnih（10 nM）处理后，在培养 7 天后，G0/G1 期细胞数量明显减少，而精原细胞细胞类型的比例面积没有明显变化。使用 BrdU（5-溴-2'-脱氧尿苷）标记进行 DNA 合成研究表明，用 zGnih（10 nM）处理可显著降低 A 型精原细胞的增殖活性，同时增加 B 型精原细胞的有丝分裂活性。我们还表明，用 zGnih（100 nM）处理可完全消除 100ng/ml Fsh 诱导的 11-KT 释放。用 zGnih（10 和 100 nM）处理也抑制了 hCG 和 Fsh 诱导的精子发生。这些结果，加上我们之前的发现，表明在睾丸中局部产生的 zGnih 是调节斑马鱼睾丸功能的复杂多因素系统的一个组成部分。
