title: In vitro effects of somatostatin on the growth hormone-insulin-like growth factor axis in orange-spotted grouper (Epinephelus coioides).
abstract: Growth in vertebrates is mainly mediated by the growth hormone (GH)-insulin-like growth factor (IGF) axis, and somatostatin (SRIF) inhibits growth by decreasing GH release at the pituitary level and antagonizing the release and action of GHRH in the hypothalamus. However, the effects of SRIF on the regulation of growth at levels other than GH release from the pituitary gland are less well known. In the present study, we comprehensively examined the pituitary and peripheral actions of SRIF on the GH-IGF axis in grouper using a primary pituitary and hepatocyte cell culture system. Our results showed that SRIF inhibited GH release at the pituitary level, but had no influence on GH mRNA expression. Basal hepatic GH receptor 1 (GHR1), IGF-I and IGF-II mRNA levels declined over time, whereas GHR2 mRNA levels remained stable throughout the culture period. GH stimulated the hepatic expression of GHR and IGF mRNAs in a dose-dependent manner, while SRIF suppressed both basal and GH-stimulated expression of GHR and IGF mRNAs in primary cultured hepatocytes. The inhibition of GHR and IGF mRNA levels by SRIF was not attributed to the rate of mRNA degradation. To the best of our knowledge, we demonstrated the effects of SRIF on basal and GH-stimulated IGF-II mRNA levels in teleosts for the first time. These results indicate that SRIF regulates growth at the level of the pituitary and peripheral liver.
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Jirong
authors.initials: J
authors.lastname: Jia
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Guokun
authors.initials: G
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Jingkai
authors.initials: J
authors.lastname: Qin
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Qiuping
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Caiyun
authors.initials: C
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China. Electronic address: lsslws@mail.sysu.edu.cn.
authors.forename: Wensheng
authors.initials: W
authors.lastname: Li
mesh_terms: D000818:Animals; D001492:Bass / Q000378:metabolism*; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000187:drug effects; D013006:Growth Hormone / Q000235:genetics / Q000378:metabolism*; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000235:genetics / Q000378:metabolism; D010902:Pituitary Gland / Q000166:cytology / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D011986:Receptors, Somatotropin / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects*; D013004:Somatostatin / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D012333:RNA, Messenger; D011986:Receptors, Somatotropin; D011994:Recombinant Proteins; D013004:Somatostatin; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D013006:Growth Hormone
keywords: Grouper; Growth hormone; Growth hormone receptor; Insulin-like growth factor; Primary cell cultures; Somatostatin