Abstract:
Thyroid stimulating hormone (TSH), a glycoprotein synthesized and secreted from thyrotrophs of the pituitary gland, is composed of a glycoprotein hormone common alpha subunit (CGA) and a specific beta subunit (TSHB). The major biological function of TSH is to stimulate thyroidal follicles to synthesize and secrete thyroid hormones through activating its cognate receptor, the thyroid stimulating hormone receptor (TSHR). In the present study, polyclonal antisera against ricefield eel Tshb and Tshr were generated respectively, and the expression of Tshb and Tshr was examined at mRNA and protein levels. RT-PCR analysis showed that tshb mRNA was expressed mainly in the pituitary as well as in some extrapituitary tissues including the ovary and testis. Tshr mRNA was also expressed in a tissue-specific manner, with transcripts detected in tissues including the kidney, ovary, and testis. The immunoreactive Tshb signals in the pituitary were shown to be localized to the inner areas of adenohypophysis which are close to the neurohypophysis of adult ricefield eels. Tshb-immunoreatvie cells in the pituitary of ricefield eel larvae were firstly observed at hatching. The expression of immunoreactive Tshb and Cga was also detected in ricefield eel ovary and testis together with Tshr. In the ovary, immunoreactive Tshb, Cga, and Tshr were observed in oocytes and granulosa cells. In the testis, immunoreactive Tshb was mainly observed in Sertoli cells while immunoreactive Cga and Tshr were detected in germ cells as well as somatic cells. Results of the present study suggest that Tsh may be synthesized both in the ovary and testis locally, which may play paracrine and/or autocrine roles in gonadal development in ricefield eels.
摘要:
促甲状腺激素(TSH),从垂体的促甲状腺激素合成和分泌的糖蛋白,由糖蛋白激素共同α亚基(CGA)和特异性β亚基(TSHB)组成。TSH的主要生物学功能是通过激活其同源受体来刺激甲状腺卵泡合成和分泌甲状腺激素。促甲状腺激素受体(TSHR)。在本研究中,分别制备了抗稻田鳗鱼Tshb和Tshr的多克隆抗血清,在mRNA和蛋白水平检测Tshb和Tshr的表达。RT-PCR分析表明,tshbmRNA主要在垂体以及包括卵巢和睾丸在内的一些垂体外组织中表达。TshrmRNA也以组织特异性方式表达,在包括肾脏在内的组织中检测到转录本,子房,和睾丸。垂体中的免疫反应性Tshb信号显示位于腺垂体的内部区域,该区域靠近成年稻田鳗鱼的神经垂体。在孵化时首先观察到稻田鳗鱼幼虫垂体中的Tshb免疫反应细胞。在稻田鳗鱼卵巢和睾丸中也检测到了免疫反应性Tshb和Cga的表达。在卵巢里,免疫反应性Tshb,Cga,在卵母细胞和颗粒细胞中观察到Tshr。在睾丸里,主要在支持细胞中观察到免疫反应性Tsh,而在生殖细胞和体细胞中检测到免疫反应性Cga和Tshr。本研究的结果表明,Tsh可能在卵巢和睾丸局部合成,可能在稻田鳗鱼的性腺发育中起旁分泌和/或自分泌作用。