Jiang Quan, Zhang Qianli, Lian Anji, Xu Yue
Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, PR China.
Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, PR China.
Anim Reprod Sci. 2017 Oct;185:140-147. doi: 10.1016/j.anireprosci.2017.06.018. Epub 2017 Aug 19.
The link between energy metabolism and reproduction is well known in vertebrates. Irisin, the product of fibronectin type III domain-containing protein 5 (FNDC5) gene, plays an important role in energy homeostasis. However, biological actions of irisin on reproduction remain elusive. To address this gap, we examined the direct effects of irisin on luteinizing hormone β (LHβ) and follicle-stimulating hormone β (FSHβ) gene expression in tilapia pituitary cells. As a first step, the transcripts of FNDC5 were detected in the proximal pars distalis (PPD), but not in the rostral pars distalis (RPD) and neurointermediate lobe (NIL) of the tilapia pituitary by RT-PCR. In the tilapia pituitary, irisin immunoreactive signals were also detected in PPD region. In primary cultures of tilapia pituitary cells, irisin was effective in stimulating both LHβ and FSHβ mRNA levels in vivo and in vitro. In cultured pituitary cells of tilapia, removal of endogenous irisin by immunoneutralization using irisin antiserum inhibited LHβ and FSHβ gene expression. Salmon gonadotrophin releasing hormone (sGnRH) increased LHβ and FSHβ mRNA levels in tilapia pituitary but these stimulatory actions were not either enhanced by treatment with irisin or blocked by irisin antiserum. Furthermore, the stimulation on LHβ and FSHβ mRNA expression was coincident with the enhancement of LHβ and FSHβ mRNA stability after irisin treatment. These results provide evidence that irisin may serve as a novel intrapituitary factor maintaining gonadotropins gene expression in tilapia pituitary.
能量代谢与生殖之间的联系在脊椎动物中是广为人知的。鸢尾素是含III型纤连蛋白结构域蛋白5（FNDC5）基因的产物，在能量稳态中发挥重要作用。然而，鸢尾素对生殖的生物学作用仍不清楚。为了填补这一空白，我们研究了鸢尾素对罗非鱼垂体细胞中促黄体生成素β（LHβ）和促卵泡生成素β（FSHβ）基因表达的直接影响。第一步，通过逆转录聚合酶链反应（RT-PCR）在罗非鱼垂体的远侧部近端（PPD）检测到FNDC5的转录本，但在远侧部前端（RPD）和神经中间叶（NIL）未检测到。在罗非鱼垂体中，也在PPD区域检测到鸢尾素免疫反应信号。在罗非鱼垂体细胞的原代培养中，鸢尾素在体内和体外均能有效刺激LHβ和FSHβ的mRNA水平。在罗非鱼培养的垂体细胞中，使用鸢尾素抗血清通过免疫中和去除内源性鸢尾素可抑制LHβ和FSHβ基因表达。鲑鱼促性腺激素释放激素（sGnRH）可增加罗非鱼垂体中LHβ和FSHβ的mRNA水平，但这些刺激作用既不会因鸢尾素处理而增强，也不会被鸢尾素抗血清阻断。此外，鸢尾素处理后对LHβ和FSHβ mRNA表达的刺激与LHβ和FSHβ mRNA稳定性的增强相一致。这些结果提供了证据，表明鸢尾素可能作为一种新的垂体内部因子维持罗非鱼垂体中促性腺激素基因的表达。
