Gene expression profiles of growth hormone, gonadotropins and proopiomelanocortin in yellow stage of wild female Japanese eel, Anguilla japonica
Date Issued
2009
Date
2009
Author(s)
Hipolito, Sheryll Grospe
Abstract
Anguilla japonica, known as the Japanese eel, is a catadromous fish that can be found in Japan, Taiwan, China and Korea. Owing to its unique life cycle, spending parts of its life in freshwater and seawater environment where they undergo multiple morphophysiological changes made it a suitable species for investigating endocrine regulatory system of teleost fish. el pituitary gland contains a variety of secretory cells which through the actions of hypothalamus target specific cell types that triggers hormonal secretions including growth hormone, reproductive hormones, proopiomelanocortin, thyrotrophin and prolactin that are important for growth, development, metabolism, reproductive and nervous system functions. Although considerable advances have been made in understanding the roles of hormones in the context of osmoregulation, reproduction, growth and differentiation and energy, some information concerning these processes and their possible interactions with each other are still lacking and needs further studies. The main objective of this study is to evaluate the potential interaction between growth hormone (GH), follicle stimulating hormone β-subunit (FSHβ), luteinizing hormone β-subunit (LHβ), glycoprotein hormone α-subunit (GPα) and proopiomelanocortin (POMC) at the pituitary level in wild caught female yellow stage Japanese eels.ild Japanese eels were obtained from the Kaoping River of Taiwan between September 2006 and March 2008. Total length and body weights were measured and morphometric indices including ocular index (OI), fin index (FI), hepatosomatic index (HSI) and gonadosomatic index (GSI) were calculated. Total RNA was extracted from individual or pooled pituitary glands and the expression levels of pituitary hormones were determined by Real-Time-qPCR. Total length showed a significant and positive correlation with OI and a negative correlation with FI while no correlations were observed with HSI and GSI. On the other hand, total length revealed no correlations with GH, FSHβ, LHβ, GPα and POMC. The results showed a significant and positive correlation of GH, FSHβ and LHβ to GSI. Correlation analysis between pituitary hormones revealed significant and positive correlations among GH, FSHβ, LHβ and POMC. However, no correlations were observed between these hormones and GPα. he results demonstrated that, at the pituitary level of yellow stage of wild female Japanese eels, hormone interaction occurs on growth hormone, reproductive hormones and proopiomelanocortin. Their interactions may be affected by downstream signaling factors, by anatomical distribution of the secretory cells resulting in paracrine communication or by dual actions of hypothalamic neuroendocrine hormones.
Subjects
Japanese eel
growth hormone
follicle stimulating hormone
luteinizing hormone
glycoprotein
proopiomelanocortin
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