title: Effects of insulin treatment on the response to oleate and octanoate of food intake and fatty acid-sensing systems in rainbow trout.
abstract: We hypothesized that food intake and the response of fatty acid (FA)-sensing systems in hypothalamus, liver, and Brockmann bodies of rainbow trout to raised levels of oleate (OL) or octanoate (OCT) is modified by insulin treatment. To assess this hypothesis, 15 fish per group received intraperitoneally 10-mL/kg injection of saline solution alone (control), or containing insulin (2-mg bovine insulin/kg body mass), OL (300 μg/kg), OCT (300 μg/kg), insulin + OL, or insulin + OCT to be sampled 6 h later to assess parameters related to FA sensing. Our results suggest that the modulatory role of insulin on the responses of hypothalamic FA-sensing systems to changes in circulating levels of OL or OCT was of minor importance in contrast to the mammalian model. However, this is in contrast with the effects observed in another experiment assessing changes in food intake after similar treatments because insulin treatment enhanced the anorectic effects of FA alone, and the effect was especially relevant (P < 0.001) for OCT, in contrast with the mammalian model where this FA is not inducing an anorectic response. In liver and Brockmann bodies, insulin treatment enhanced the responses to OL or OCT treatment in parameters related to FA sensing. Therefore, we provide for the first time in fish, and in a non-mammalian vertebrate, evidence for the modulation of FA-sensing systems by insulin.
authors.affiliation: Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Librán-Pérez
authors.affiliation: Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Velasco
authors.affiliation: Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Otero-Rodiño
authors.affiliation: Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: López-Patiño
authors.affiliation: Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Míguez
authors.affiliation: Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain. Electronic address: jsoengas@uvigo.es.
authors.forename: J L
authors.initials: JL
authors.lastname: Soengas
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002210:Caprylates / Q000737:chemistry / Q000494:pharmacology*; D004032:Diet / Q000662:veterinary; D005227:Fatty Acids / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D007328:Insulin / Q000494:pharmacology*; D019301:Oleic Acid / Q000737:chemistry / Q000494:pharmacology*; D017686:Oncorhynchus mykiss; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D002210:Caprylates; D005227:Fatty Acids; D007328:Insulin; D012333:RNA, Messenger; D019301:Oleic Acid; C031492:octanoic acid
keywords: Fatty acid–sensing; Food intake; Hypothalamus; Insulin; Liver; Trout