Amino Acids Are a Source of Glycerol in Cold-Acclimatized Rainbow Smelt

Rainbow smelt (Osmerus mordax) produce high concentrations of glycerol in winter to protect against freezing. The glycerol is lost to the environment and so must be continually replaced. Glycogen has previously been shown to be a source of glycerol in this species, but glycerol levels are maintained...

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Bibliographic Details
Published in:Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 1997-10, Vol.118 (2), p.387-393
Main Authors: Raymond, James A, Driedzic, William R
Format: Article
Language:English
Subjects:
alanine
amino acids
bicarbonate
cold hardiness
gluconeogenesis
glutamate
glycerol synthesis
Marine
Osmerus mordax
Rainbow smelt
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Summary:Rainbow smelt (Osmerus mordax) produce high concentrations of glycerol in winter to protect against freezing. The glycerol is lost to the environment and so must be continually replaced. Glycogen has previously been shown to be a source of glycerol in this species, but glycerol levels are maintained even when glycogen levels have been depleted. In the present study, using radiolabeled substrates, it is qualitatively shown that the carbon skeletons of alanine and glutamate are largely converted to glycerol and glucose in −1°C-acclimatized smelt, suggesting that protein is another important source of glycerol. Bicarbonate carbon was also largely converted to glycerol and glucose, apparently through its involvement in the conversion of amino acids to oxaloacetate. Together, these results indicate an active gluconeogenesis in winter-acclimatized rainbow smelt.
ISSN:1096-4959
0305-0491
1879-1107
DOI:10.1016/S0305-0491(97)00178-8