Pinto P, Velez Z, Sousa C, Santos S, Andrade A, Alvarado M V, Felip A, Zanuy S, Canário A V M
CCMAR-Centro de Ciências do Mar, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
CCMAR-Centro de Ciências do Mar, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
Gen Comp Endocrinol. 2017 Sep 1;250:152-161. doi: 10.1016/j.ygcen.2017.06.009. Epub 2017 Jun 19.
The neuropeptide galanin (Gal) is a putative factor regulating puberty onset and reproduction through its actions on the pituitary. The present study investigated the pituitary responsiveness to galanin and the patterns of galanin receptors (Galrs) expression throughout the reproductive cycle of two years old male European sea bass (Dicentrarchus labrax), an important aquaculture species. Quantitative analysis of pituitary and hypothalamus transcript expression of four galr subtypes revealed differential regulation according to the testicular developmental stage, with an overall decrease in expression from the immature stage to the mid-recrudescence stage. Incubation of pituitary cells with mammalian 1-29Gal peptide induced significant changes in cAMP concentration, with sensitivities that varied according to the testicular development stages. Furthermore 1-29Gal was able to stimulate both follicle stimulating hormone (Fsh) and luteinizing hormone (Lh) release from pituitary cell suspensions. The magnitude of the effects and effective concentrations varied according to reproductive stage, with generalized induction of Fsh and Lh release in animals sampled in January (full spermiation). The differential expression of galrs in pituitary and hypothalamus across the reproductive season, together with the differential effects of Gal on gonadotropins release in vitro strongly suggests the involvement of the galaninergic system in the regulation the hypothalamus-pituitary-gonad axis of male sea bass. This is to our knowledge the first clear evidence for the involvement of galanin in the regulation of reproduction in non-mammalian vertebrates.
神经肽甘丙肽（Gal）是一种推测通过作用于垂体来调节青春期启动和生殖的因子。本研究调查了两岁雄性欧洲海鲈（Dicentrarchus labrax，一种重要的水产养殖物种）在整个生殖周期中垂体对甘丙肽的反应以及甘丙肽受体（Galrs）的表达模式。对四种Galr亚型的垂体和下丘脑转录本表达进行定量分析，结果显示根据睾丸发育阶段存在差异调节，从未成熟阶段到中期恢复期表达总体下降。用哺乳动物1 - 29Gal肽孵育垂体细胞会引起cAMP浓度的显著变化，其敏感性因睾丸发育阶段而异。此外，1 - 29Gal能够刺激垂体细胞悬液释放促卵泡激素（Fsh）和促黄体生成素（Lh）。效应的大小和有效浓度因生殖阶段而异，在1月采样的动物（完全精子发生）中普遍诱导Fsh和Lh释放。在整个生殖季节，垂体和下丘脑中Galrs的差异表达，以及Gal对体外促性腺激素释放的差异效应，强烈表明甘丙肽能系统参与调节雄性海鲈的下丘脑 - 垂体 - 性腺轴。据我们所知，这是甘丙肽参与非哺乳类脊椎动物生殖调节的首个明确证据。
