在马苏大麻哈鱼早熟雄鱼分化之前，鲑鱼促性腺激素释放激素（GnRH）信使核糖核酸（mRNA）表达的激活。

Activation of salmon GnRH mRNA expression prior to differentiation of precocious males in Masu salmon.

作者信息

Amano M, Kitamura S, Ikuta K, Suzuki Y, Aida K

机构信息

Nikko Branch, National Research Institute of Aquaculture, Tochigi, Japan.

出版信息

Gen Comp Endocrinol. 1997 Mar;105(3):365-71. doi: 10.1006/gcen.1996.6838.

DOI:10.1006/gcen.1996.6838

PMID:9073498

Abstract

Changes in salmon gonadotropin-releasing hormone (sGnRH) mRNA levels in the brain of underyearling male masu salmon, Oncorhynchus masou, were investigated to clarify sGnRH participation in differentiation of precocious males. Fish were immature with low gonadosomatic index (GSI < 0.100%) on April 16 and May 7. On June 11, fish were differentiated into two groups: future precocious males and immature males. Fish in the former group had high GSI (0.203%) with proliferation of primary spermatocytes in the testis, while the latter had low GSI (0.055%) with primary spermatogonia. sGnRH mRNA levels (the number of neurons expressing sGnRH mRNA and the total number of silver grains per unit area) in the ventral telencephalon (VT) and in the VT plus preoptic area (POA) already increased in May before the differentiation of precocious males. GSI was positively correlated with sGnRH mRNA levels in the VT and in the VT plus POA in April, and with mRNA levels in the POA in May. Activated sGnRH synthesis is concluded to be related to the appearance of precocious males in masu salmon.

摘要

为了阐明鲑鱼促性腺激素释放激素（sGnRH）在马苏大麻哈鱼（Oncorhynchus masou）幼龄雄性个体大脑中对早熟雄性分化的参与情况，对其大脑中sGnRH信使核糖核酸（mRNA）水平的变化进行了研究。4月16日和5月7日时，鱼处于未成熟状态，性腺体指数较低（GSI < 0.100%）。6月11日，鱼被分为两组：未来的早熟雄性和未成熟雄性。前一组鱼的GSI较高（0.203%），睾丸中的初级精母细胞增殖，而后一组鱼的GSI较低（0.055%），含有初级精原细胞。在早熟雄性分化之前的5月，腹侧端脑（VT）以及VT加视前区（POA）中的sGnRH mRNA水平（表达sGnRH mRNA的神经元数量和每单位面积银颗粒总数）就已经升高。4月时，GSI与VT以及VT加POA中的sGnRH mRNA水平呈正相关，5月时与POA中的mRNA水平呈正相关。得出结论，sGnRH合成的激活与马苏大麻哈鱼早熟雄性的出现有关。