title: Increased growth hormone (GH), growth hormone receptor (GHR), and insulin-like growth factor I (IGF-I) gene transcription after hyperosmotic stress in the Brazilian flounder Paralichthys orbignyanus.
abstract: Growth hormone (GH) action is the result of an intracellular cascade initiated just after its interaction with the growth hormone receptor (GHR) located on the surface of target cells. This cascade culminates with the transcription of target genes, such as the insulin-like growth factors (IGFs), which are responsible for most GH biological effects. In addition to its central role in growth, fish GH is also involved with osmoregulatory control. Within this context, the objective of the present work was to isolate GH, GHR, and IGF-I cDNAs from the Brazilian flounder Paralichthys orbignyanus and evaluate whether these genes are induced by hyperosmotic stress. The obtained results indicated that GH mRNA had a significant peak only 24 h after hyperosmotic stress. In gills, GHR mRNA was significantly increased after 7 days. In liver, GHR and IGF-I mRNAs were significantly increased in 72 h and both reached even higher levels after 7 days. These results indicate that hyperosmotic stress can increase GH sensitivity in the gills and liver of P. orbignyanus and, consequently, improve IGF-I production. The management of this parameter could be useful in achieving better growth performance for this and other commercially important species in which GH has a direct correlation with osmoregulatory mechanisms.
authors.affiliation: Instituto de Ciências Biológicas, Universidade Federal do Rio Grande-FURG, Rio Grande, RS, Brazil.
authors.forename: Karina M
authors.initials: KM
authors.lastname: Meier
authors.forename: Márcio A
authors.initials: MA
authors.lastname: Figueiredo
authors.forename: Michel T
authors.initials: MT
authors.lastname: Kamimura
authors.forename: Jomar
authors.initials: J
authors.lastname: Laurino
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Maggioni
authors.forename: Luciano S
authors.initials: LS
authors.lastname: Pinto
authors.forename: Odir A
authors.initials: OA
authors.lastname: Dellagostin
authors.forename: Marcelo B
authors.initials: MB
authors.lastname: Tesser
authors.forename: Luís A
authors.initials: LA
authors.lastname: Sampaio
authors.forename: Luis F
authors.initials: LF
authors.lastname: Marins
mesh_terms: D000818:Animals; D017756:Aquaculture / Q000379:methods; D001938:Brazil; D017931:DNA Primers / Q000235:genetics; D005432:Flounder / Q000235:genetics / Q000502:physiology*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000502:physiology*; D005880:Gills / Q000378:metabolism; D013006:Growth Hormone / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D009997:Osmotic Pressure; D011986:Receptors, Somatotropin / Q000378:metabolism*; D014882:Water-Electrolyte Balance / Q000502:physiology*
chemical_list: D017931:DNA Primers; D011986:Receptors, Somatotropin; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone