title: Metabolic response in liver and Brockmann bodies of rainbow trout to inhibition of lipolysis; possible involvement of the hypothalamus-pituitary-interrenal (HPI) axis.
abstract: We previously demonstrated in rainbow trout that the decrease in circulating levels of fatty acid (FA) induced by treating fish with SDZ WAG 994 (SDZ) induced a counter-regulatory response in which the activation of the hypothalamus-pituitary-interrenal (HPI, equivalent to mammalian hypothalamus-pituitary-adrenal) axis was likely involved. This activation, probably not related to the control of food intake through FA sensor systems but to the modulation of lipolysis in peripheral tissues, liver and Brockmann bodies (BB, the main site of pancreatic endocrine cells in fish), would target the restoration of FA levels in plasma. To assess this hypothesis, we lowered circulating FA levels by treating fish with SDZ alone, or SDZ in the presence of metyrapone (an inhibitor of cortisol synthesis). In liver, the changes observed were not compatible with a direct FA-sensing response but with a stress response, which allows us to suggest that the detection of a FA decrease in the hypothalamus elicits a counter-regulatory response in liver, resulting in an activation of lipolysis to restore FA levels in plasma. The activation of these metabolic changes in liver could be attributable to the activation of the HPI axis and/or to the action of sympathetic pathways. In contrast, in BB, changes in circulating FA levels induce changes in several parameters compatible with the function of FA-sensing systems informing about the decrease in circulating FA levels.
authors: Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Edificio de Ciencias Experimentais, Universidade de Vigo, 36310, Vigo, Spain.
authors: Marta
authors: M
authors: Librán-Pérez
authors: Cristina
authors: C
authors: Velasco
authors: Cristina
authors: C
authors: Otero-Rodiño
authors: Marcos A
authors: MA
authors: López-Patiño
authors: Jesús M
authors: JM
authors: Míguez
authors: José L
authors: JL
authors: Soengas
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D017931:DNA Primers / Q000235:genetics; D005227:Fatty Acids / Q000097:blood*; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D007401:Interrenal Gland / Q000502:physiology; D008066:Lipolysis / Q000187:drug effects / Q000502:physiology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008797:Metyrapone; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D010179:Pancreas / Q000378:metabolism*; D010913:Pituitary-Adrenal System / Q000502:physiology*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D005227:Fatty Acids; C090949:N(6)-cyclohexyl-2-O-methyladenosine; D000241:Adenosine; D008797:Metyrapone