Comparison of liver enzymes in osmerid fishes: key differences between a glycerol accumulating species, rainbow smelt (Osmerus mordax), and a species that does not accumulate glycerol, capelin (Mallotus villosus)

Comp Biochem Physiol A Mol Integr Physiol. 2002 Jun;132(2):433-8. doi: 10.1016/s1095-6433(02)00083-1.

Abstract

Activities of enzymes associated with glycerol synthesis were compared in the liver of two osmerid fishes, the smelt (Osmerus mordax), which can accumulate high (400 mM) levels of glycerol and capelin (Mallotus villosus) that does not accumulate glycerol. Animals were sampled at approximately the same time of year and temperature thus negating potential seasonal effects. These species are closely related, reducing interpretative issues involving comparison between unrelated species. We found that key enzyme activities were elevated in the smelt relative to the non-glycerol accumulating capelin, namely enzymes involved with glycolysis (phosphofructose kinase-1 and aldolase), amino acid metabolism (aspartate aminotransferase and alanine aminotransferase), gluconeogenesis (phosphoenolpyruvate carboxykinase) and glycerol synthesis (glycerol-3-phosphate dehydrogenase). The enzyme profiles strongly support the hypothesis that smelt can synthesize glycerol by utilizing glycogen and amino acids as the carbon source and that they have increased capacity for metabolic flux through loci required for synthesis of the three carbon intermediate dihydroxyacetone phosphate and subsequently glycerol synthesis.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / metabolism
  • Animals
  • Fishes / metabolism*
  • Gluconeogenesis
  • Glycerol / metabolism*
  • Glycerolphosphate Dehydrogenase / metabolism
  • Glycolysis
  • Liver / enzymology*
  • Liver / metabolism
  • Malates / metabolism
  • Osmeriformes / metabolism
  • Seasons
  • Species Specificity

Substances

  • Amino Acids
  • Malates
  • malic acid
  • Glycerolphosphate Dehydrogenase
  • Glycerol