Please use this identifier to cite or link to this item: https://doi.org/10.1016/j.cbpa.2008.06.003
Title: Carbohydrate and amino acid metabolism in fasting and aestivating African lungfish (Protopterus dolloi)
Authors: Frick, N.T.
Bystriansky, J.S.
Ip, Y.K. 
Chew, S.F.
Ballantyne, J.S.
Keywords: Aestivation
Amino acid metabolism
Carbohydrate metabolism
Glycogen
Glycolysis
Lactate
Protopterus
Issue Date: Sep-2008
Citation: Frick, N.T., Bystriansky, J.S., Ip, Y.K., Chew, S.F., Ballantyne, J.S. (2008-09). Carbohydrate and amino acid metabolism in fasting and aestivating African lungfish (Protopterus dolloi). Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology 151 (1) : 85-92. ScholarBank@NUS Repository. https://doi.org/10.1016/j.cbpa.2008.06.003
Abstract: The potential importance of carbohydrates and amino acids as fuels during periods of fasting and aestivation in the African lungfish, Protopterus dolloi, were examined. No significant decreases in tissue glycogen levels were observed following 60 days of fasting or aestivation, suggesting lungfish may undergo 'glycogen sparing'. Yet glycogenolysis may be important during aestivation based on the differing responses of two flux-generating enzymes of the glycolytic pathway, hexokinase (HK) and pyruvate kinase (PK). PK is required for glycogen breakdown whereas HK is not. HK activity is significantly down-regulated in the heart and gill tissues during aestivation, while PK activity is sustained. The significant negative correlation between the activity of HK and glucose levels in the heart of aestivating lungfish suggests HK may be regulated by glucose concentrations. There was no indication of anaerobic glycolytic flux during aestivation as lactate did not accumulate in any of the tissues examined, and no significant induction of lactate dehydrogenase (LDH) activity was observed. The increase in glutamate dehydrogenase (GDH) and aspartate aminotransferase (Asp-AT) activities in the liver of aestivating P. dolloi suggests some energy may be obtained via increased amino acid catabolism, leading to the generation of tricarboxylic acid (TCA) cycle intermediates. These findings indicate the importance of both carbohydrate and amino acid fuel stores during aestivation in a phylogenetically ancient, air-breathing fish. © 2008 Elsevier Inc. All rights reserved.
Source Title: Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology
URI: http://scholarbank.nus.edu.sg/handle/10635/100213
ISSN: 10956433
DOI: 10.1016/j.cbpa.2008.06.003
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