Nom du corpus

Corpus Systématique Animale

Titre du document

Are cell redox or lactate dehydrogenase kinetics responsible for the absence of gluconeogenesis from lactate in sea raven, hepatocytes?

Lien vers le document
Éditeur
Springer (journals)
Langue(s) du document
Anglais
Type de document
Research-article
Mots-clés d'auteur
  • fish
  • sea raven
  • gluconeogensis
  • hepatocytes
  • redox
  • LDH
  • isozymes
  • kinetics
Nom du fichier dans la ressource
Mammiferes_v2b_01853
Auteur(s)
  • Glen D. Foster 1
  • J. Zhang 1
  • T. W. Moon 1
Affiliation(s)
  • 1) Huntsman Marine Science Centre, St. Andrews, EOG 2X0, New Brunswick, Canada
Résumé

Previous studies have reported very low rates of gluconeogenesis from lactate in sea raven (Hemitripterus americanus) hepatocytes compared to other teleosts studied. This study examines whether hepatic cell redox or lactate dehydrogenase (LDH) characteristics may explain this observation. Sea raven hepatic optimal LDH activities (pyruvate reductase direction) were more than 40 times less compared with rainbow trout liver values (40 vs 1914 ?mol·min?1·g?1 protein). The Km(lactate) was 9.24 and 0.86 mM for sea raven and trout hepatic LDH, but the Km(pyruvate) was similar between the two species (0.11 and 0.21 mM, respectively). These results suggested that sea raven liver LDH did not favour lactate use and was more indicative of the mammalian M-isozyme. Gel electrophoresis showed a predominant intermediate isozyme, with a small amount of the M-type LDH. Phosphoenolpyruvate carboxykinase (PEPCK) was localized to the mitochondrial compartment, while there was no apparent mitochondrial glutamate-oxaloacetate transaminase (GOT) activity. No in vitro lactate flux to glucose was found in untreated, 10 mM ethanol-treated, or 3 mM NH4Cl-treated sea raven hepatocytes, although CO2 production from lactate was decreased by ethanol and increased by NH4Cl. These results provide evidence that cell redox does not limit gluconeogenesis from lactate, while low activities and the kinetic characteristics of LDH may partially explain the low lactate gluconeogenesis reported in sea raven hepatocytes.

Catégories Science-Metrix
  • 1 - applied sciences
  • 2 - agriculture, fisheries & forestry
  • 3 - fisheries
Catégories INIST
  • 1 - sciences appliquees, technologies et medecines
  • 2 - sciences biologiques et medicales
  • 3 - sciences biologiques fondamentales et appliquees. psychologie
Catégories Scopus
  • 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - Aquatic Science
  • 1 - Health Sciences ; 2 - Medicine ; 3 - General Medicine
  • 1 - Life Sciences ; 2 - Biochemistry, Genetics and Molecular Biology ; 3 - Physiology
  • 1 - Life Sciences ; 2 - Biochemistry, Genetics and Molecular Biology ; 3 - Biochemistry
Catégories WoS
  • 1 - science ; 2 - physiology
  • 1 - science ; 2 - fisheries
  • 1 - science ; 2 - biochemistry & molecular biology
Identifiant ISTEX
0AE833E194668A71D48EDCA0348001CF76BAC642
Revue

Fish Physiology and Biochemistry

Année de publication
1994
Présence de XML structuré
Non
Version PDF
1.3
Score qualité du texte
8.953
Sous-corpus
  • Mammiferes
Type de publication
Journal
ark:/67375/1BB-7T49RR92-P
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