Gonadotropin-releasing hormone receptor (GnRHR) gene expression is differently modulated.in gender types of the hermaphroditic fish Kryptolebias marmoratus by endocrine disrupting chemicals

作者：Rhee Jae Sung; Seo Jung Soo; Raisuddin Sheikh; Ki Jang Seu; Lee Kyun Woo; Kim Il Chan; Yoon Yong Dal; Lee Jae Seong^*

来源：Comparative Biochemistry and Physiology C-Toxicology & Pharmacology, 2008, 147(3): 357-365.

DOI：10.1016/j.cbpc.2008.01.007

• Kryptolebias marmoratus
• gonadotropin-releasing hormone receptor
• endocrine-disrupting chemicals
• modulation

Gonadotropin-releasing hormone (GnRH) plays a pivotal role in the regulation of reproduction in vertebrates through interaction with a specific receptor. The GnRH-stimulated gonadotropin synthesis and release are regulated by the GnRH receptors (GnRHRs). In this study, we have identified a GnRH receptor (GnRHR) gene from the hermaphroditic fish Kryptolebias marmoratus. K marmoratus GnRHR showed typical vertebrate GnRHR domains and motifs, and its eDNA contained 1634 by including an open reading frame (ORF) of 1263 by encoding a putative protein of 420 amino acids. To analyze expression patterns of GnRHR gene in various tissues and developmental stages of K marmoratus, we carried out quantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR). The K marmoratus GnRHR gene expression was detected in all the tissues of adult fish with highest level in brain and gonad. The expression of K marmoratus GnRHR mRNA increased from stage 1 (2 day post fertilization, dpf) to stage 4 (12 dpf) but steeply decreased at hatching stage (stage 5). Expression of K marmoratus GnRHR after exposure to endocrine-disrupting chemicals such bisphenol A (BPA, 600 mu g/L for 96 h) and 4-tert-octylphenol (OP, 300 mu g/L for 96 h) in hermaphrodites as well as secondary males was highly up-regulated in almost all the tissues. Another EDC, 4-nonylphenol (NP, 300 mu g/L for 96 h) showed no consistent response. 17 beta-estrodiol (E2, 100 ng/L for 96 h), a known natural estrogen, suppressed expression of GnRHR in most of the tissues from hermaphrodites as well as secondary males. Tamoxifen (TMX, 10 mu g/L), an estrogen antagonist, on the other hand, caused upregulation of GnRHR expression in the liver of hermaphrodites and the gonad and liver of secondary males. This is the first report of a GnRHR gene from K marmoratus and modulation of its expression by EDCs. This study provides an insight into the molecular mechanism of endocrinological functions of this unique fish.

• 出版日期2008-4
• 单位中国极地研究中心