title: GH indirectly enhances the regeneration of transgenic zebrafish fins through IGF2a and IGF2b.
abstract: The somatotropic axis, composed essentially of the growth hormone (GH) and insulin-like growth factors (IGFs), is the main regulator of somatic growth in vertebrates. However, these protein hormones are also involved in various other major physiological processes. Although the importance of IGFs in mechanisms involving tissue regeneration has already been established, little is known regarding the direct effects of GH in these processes. In this study, we used a transgenic zebrafish (Danio rerio) model, which overexpresses GH from the beta-actin constitutive promoter. The regenerative ability of the caudal fin was assessed after repeated amputations, as well as the expression of genes related to the GH/IGF axis. The results revealed that GH overexpression increased the regenerated area of the caudal fin in transgenic fish after the second amputation. Transgenic fish also presented a decrease in gene expression of the GH receptor (ghrb), in opposition to the increased expression of the IGF1 receptors (igf1ra and igf1rb). These results suggest that transgenic fish have a higher sensitivity to IGFs than to GH during fin regeneration. With respect to the different IGFs produced locally, a decrease in igf1a expression and a significant increase in both igf2a and igf2b expression was observed, suggesting that igf1a is not directly involved in fin regeneration. Overall, the results revealed that excess GH enhances fin regeneration in zebrafish through igf2a and igf2b expression, acting indirectly on this major physiological process.
authors.affiliation: Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Av. Itália Km 8, CEP 96203-900, Rio Grande, RS, Brazil.
authors.forename: Bruna Félix
authors.initials: BF
authors.lastname: Nornberg
authors.affiliation: Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Av. Itália Km 8, CEP 96203-900, Rio Grande, RS, Brazil.
authors.forename: Daniela Volcan
authors.initials: DV
authors.lastname: Almeida
authors.affiliation: Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Av. Itália Km 8, CEP 96203-900, Rio Grande, RS, Brazil.
authors.forename: Márcio Azevedo
authors.initials: MA
authors.lastname: Figueiredo
authors.affiliation: Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Av. Itália Km 8, CEP 96203-900, Rio Grande, RS, Brazil. dqmluf@furg.br.
authors.forename: Luis Fernando
authors.initials: LF
authors.lastname: Marins
mesh_terms: D058500:Animal Fins / Q000254:growth & development; D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics; D005786:Gene Expression Regulation; D013006:Growth Hormone / Q000235:genetics*; D011986:Receptors, Somatotropin / Q000235:genetics*; D012038:Regeneration / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics; D013002:Somatomedins / Q000235:genetics*; D014945:Wound Healing / Q000235:genetics; D015027:Zebrafish / Q000235:genetics / Q000254:growth & development; D029961:Zebrafish Proteins / Q000235:genetics*
chemical_list: C000596542:Igf2a protein, zebrafish; C000596543:Igf2b protein, zebrafish; D011986:Receptors, Somatotropin; D013002:Somatomedins; D029961:Zebrafish Proteins; D013006:Growth Hormone
keywords: Fin regeneration; Gene expression; Growth hormone (GH); Insulin-like growth factor (IGF); Transgenic zebrafish