title: Regulation of plasma insulin-like growth factor-I levels in brown trout (Salmo trutta).
abstract: In this study we report that the use of a heterologous radioimmunoassay (RIA) is valid for the detection of insulin-like growth factor-I (IGF-I) levels in plasma of a variety of fish species. Parallelism between standard curves and plasma dilutions were observed and the standard curve obtained with mammalian IGF-I presented the same characteristics as that obtained with coho salmon recombinant IGF-I. The RIA was biologically validated since total plasma IGF-I values were significantly modified by different experimental conditions. Hyperinsulinemia induced either by arginine or insulin injection was accompanied by increases in IGF-I plasma levels in brown trout (Salmo trutta). In contrast, parallel decreases in insulin and IGF-I circulating levels were observed after 45 days of fasting and 20 days after a single streptozotocin injection. Administration of arginine in fasted fish led to a relative increase in insulin and IGF-I plasma concentrations, while arginine injection in fish previously treated with streptozotocin increased IGF-I levels only. The above data suggest that insulin, together with other factors, may act to increase the levels of IGF-I in plasma.
authors.affiliation: Department de Fisiologia, Facultat de Biologia, Universitat de Barcelona, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Baños
authors.forename: J V
authors.initials: JV
authors.lastname: Planas
authors.forename: J
authors.initials: J
authors.lastname: Gutiérrez
authors.forename: I
authors.initials: I
authors.lastname: Navarro
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D001120:Arginine / Q000494:pharmacology; D003429:Cross Reactions; D005069:Evaluation Studies as Topic; D005215:Fasting / Q000097:blood; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood / Q000494:pharmacology; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000276:immunology / Q000378:metabolism*; D008297:Male; D011863:Radioimmunoassay / Q000379:methods / Q000662:veterinary; D015203:Reproducibility of Results; D012474:Salmon; D013311:Streptozocin / Q000494:pharmacology; D014337:Trout / Q000097:blood*
chemical_list: D000906:Antibodies; D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1; D013311:Streptozocin; D007334:Insulin-Like Growth Factor I; D001120:Arginine