title: Intraspecific variation in aerobic metabolism and glycolytic enzyme expression in heart ventricles.
abstract: A previous phylogenetic analysis among 15 taxa of the teleost fish Fundulus suggested that there should be thermal-adaptive differences in heart metabolism among populations. To test this hypothesis, the rate of oxygen consumption and the activities of all 11 glycolytic enzymes were measured in isolated heart ventricle from two populations of Fundulus heteroclitus. Heart ventricular metabolism is greater in a northern population versus a southern population of these fish. Analysis of the amount of glycolytic enzymes indicates that 87% of the variation in cardiac metabolism within and between populations is explained by the variation in three enzymes (pyruvate kinase, glyceraldehyde-3-phosphate dehydrogenase, and lactate dehydrogenase). These enzymes are the same three enzymes that were predicted to be important based on previously determined phylogenetic patterns of expression. Our data indicate that near-equilibrium enzymes, as well as classically defined rate-limiting enzymes, can also influence metabolism.
authors.affiliation: Section of Integrative Physiology and Neurobiology, Department of Environmental, Population and Organismal Biology, University of Colorado, Boulder, Colorado 80309-0334, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Podrabsky
authors.forename: C
authors.initials: C
authors.lastname: Javillonar
authors.forename: S C
authors.initials: SC
authors.lastname: Hand
authors.forename: D L
authors.initials: DL
authors.lastname: Crawford
mesh_terms: D000064:Acclimatization; D000332:Aerobiosis; D000818:Animals; D002140:California; D002980:Climate; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism; D006019:Glycolysis; D006352:Heart Ventricles; D007695:Killifishes / Q000145:classification / Q000502:physiology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008281:Maine; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption; D011770:Pyruvate Kinase / Q000378:metabolism; D013045:Species Specificity
chemical_list: D007770:L-Lactate Dehydrogenase; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D011770:Pyruvate Kinase