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    • Keywords


      Anisotonicity; cell volume; Clarias batrachus ; fructose 1,6-bisphosphatase; gluconeogenesis; glucose 6-phosphatase; hydration status; osmotic stress; phosphoenolpyruvate carboxykinase; pyruvate carboxylase

    • Abstract


      In addition to lactate and pyruvate, some amino acids were found to serve as potential gluconeogenic substrates in the perfused liver ofClarias batrachus. Glutamate was found to be the most effective substrate, followed by lactate, pyruvate, serine, ornithine, proline, glutamine, glycine, and aspartate. Four gluconeogenic enzymes, namely phosphoenolpyruvate carboxykinase (PEPCK), pyruvate carboxylase (PC), fructose 1,6-bisphosphatase (FBPase) and glucose 6-phosphatase (G6Pase) could be detected mainly in liver and kidney, suggesting that the latter are the two major organs responsible for gluconeogenic activity in this fish. Hypo-osmotically induced cell swelling caused a significant decrease of gluconeogenic efflux accompanied with significant decrease of activities of PEPCK, FBPase and G6Pase enzymes in the perfused liver. Opposing effects were seen in response to hyperosmotically induced cell shrinkage. These changes were partly blocked in the presence of cycloheximide, suggesting that the aniso-osmotic regulations of gluconeogenesis possibly occurs through an inverse regulation of enzyme proteins and/or a regulatory protein synthesis in this catfish. In conclusion, gluconeogenesis appears to play a vital role inC. batrachus in maintaining glucose homeostasis, which is influenced by cell volume changes possibly for proper energy supply under osmotic stress.

    • Author Affiliations


      Carina Goswami1 Shritapa Datta1 Kuheli Biswas1 Nirmalendu Saha1

      1. Biochemical Adaptation Laboratory, Department of Zoology, North-Eastern Hill University, Shillong - 793 022, India
    • Dates

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