Gluconeogenic pathway does not display metabolic cold adaptation in liver of Antarctic notothenioid fish

• Published in: Polar Biology
• Main Authors: Magnoni, Leonardo Julián, Scarlato, Norberto A., Ojeda, F. Patricio, Wöhler, Otto C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer
• Subjects: Gluconeogenesis; Glycerol; Tag Mobilization; Antarctic Notothenioid Fish; Metabolic Cold Adaptation; https://purl.org/becyt/ford/1.6; https://purl.org/becyt/ford/1; Antarctic; Argentina; Antarc*; Polar Biology
• Online Access: http://hdl.handle.net/11336/24151

Antarctic notothenioid fish display specializations related to cope with their chronically cold environment, such as high triacylglycerol (TAG) content in tissues. The metabolic fate of glycerol, a product of TAG mobilization, has not been studied in Antarctic fish. To assess the importance of glycerol as a substrate for gluconeogenesis and to determine whether this pathway is metabolically cold adapted (MCA), key hepatic enzyme activities were measured in Antarctic (Notothenia coriiceps, Gobionotothen gibberifrons, and Chionodraco rastrospinosus) and nonAntarctic (Dissostichus eleginoides, Patagonotothen ramsayi, and Eleginops maclovinus) notothenioid fish. Fructose 1,6-biphosphatase (FBP), phosphoenolpyruvate carboxykinase (PEPCK), and glycerol kinase (GK) activities were similar in both groups at common temperatures (1, 6, 11, or 21 C). In particular, thermal sensitivity for the reactions catalyzed by FBP and PEPCK was analogous between Antarctic and non-Antarctic species, reflected by similar values for Arrhenius energy of activation (Ea) and Q10. Additionally, hepatic glycerol, glucose, and glycogen contents together with plasma glycerol and glucose concentrations were similar for all of the species studied. Our results do not support the concept of MCA in hepatic gluconeogenesis and may indicate that the use of glycerol as a precursor for glucose synthesis by this pathway is of low physiological importance in Antarctic fish. Fil: Magnoni, Leonardo Julián. University Of Maine; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas Argentina Fil: Scarlato, Norberto A. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Ojeda, F. Patricio. Pontificia Universidad Católica de Chile; Chile Fil: Wöhler, Otto C. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones ...