title: Energy metabolism of hyperthyroid gilthead sea bream Sparus aurata L.
abstract: Thyroid hormones, in particular 3,5,3'-triiodothyronine or T3, are involved in multiple physiological processes in mammals such as protein, fat and carbohydrate metabolism. However, the metabolic actions of T3 in fish are still not fully elucidated. We therefore tested the effects of T3 on Sparus aurata energy metabolism and osmoregulatory system, a hyperthyroid-induced model that was chosen. Fish were implanted with coconut oil depots (containing 0, 2.5, 5.0 and 10.0μg T3/g body weight) and sampled at day 3 and 6 post-implantation. Plasma levels of free T3 as well as glucose, lactate and triglyceride values increased with increasing doses of T3 at days 3 and 6 post-implantation. Changes in plasma and organ metabolite levels (glucose, glycogen, triglycerides, lactate and total α amino acid) and enzyme activities related to carbohydrate, lactate, amino acid and lipid pathways were detected in organs involved in metabolism (liver) and osmoregulation (gills and kidney). Our data implicate that the liver uses amino acids as an energy source in response to the T3 treatment, increasing protein catabolism and gluconeogenic pathways. The gills, the most important extruder of ammonia, are fuelled not only by amino acids, but also by lactate. The kidney differs significantly in its substrate preference from the gills, as it obtained metabolic energy from lactate but also from lipid oxidation processes. We conclude that in S. aurata lipid catabolism and protein turnover are increased as a consequence of experimentally induced hyperthyroidism, with secondary osmoregulatory effects.
authors.affiliation: Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile. Electronic address: luis.vargas@uach.cl.
authors.forename: Luis
authors.initials: L
authors.lastname: Vargas-Chacoff
authors.affiliation: Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Campus de Excelencia Internacional del Mar (CEI·MAR), Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Ruiz-Jarabo
authors.affiliation: Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Arjona
authors.affiliation: Instituto Español de Oceanografía, Centro Oceanográfico de Málaga, 29640 Málaga, Spain.
authors.forename: Raúl
authors.initials: R
authors.lastname: Laiz-Carrión
authors.affiliation: Department of Organismal Animal Physiology, Institute for Water and Wetland Research, Faculty of Science, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
authors.forename: Gert
authors.initials: G
authors.lastname: Flik
authors.affiliation: Department of Organismal Animal Physiology, Institute for Water and Wetland Research, Faculty of Science, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
authors.forename: Peter H M
authors.initials: PHM
authors.lastname: Klaren
authors.affiliation: Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Campus de Excelencia Internacional del Mar (CEI·MAR), Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Mancera
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D004734:Energy Metabolism; D005880:Gills / Q000378:metabolism; D006980:Hyperthyroidism / Q000097:blood / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D016014:Linear Models; D008099:Liver / Q000378:metabolism; D055442:Metabolome; D009994:Osmolar Concentration; D021541:Sea Bream / Q000097:blood / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D016019:Survival Analysis; D014284:Triiodothyronine / Q000097:blood
chemical_list: D014284:Triiodothyronine; D000254:Sodium-Potassium-Exchanging ATPase
keywords: 3,5,3′-Triiodo-l-thyronine (T(3)); Energy metabolism; Lipid catabolism; Osmoregulation; Protein catabolism; Sparus aurata