Exercise and recovery metabolism in the pacific spiny dogfish (Squalus acanthias)

J. G. Richards, G. J F Heigenhauser, C. M. Wood

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

We examined the effects of exhaustive exercise and post-exercise recovery on white muscle substrate depletion and metabolite distribution between white muscle and blood plasma in the Pacific spiny dogfish, both in vivo and in an electrically stimulated perfused tail-trunk preparation. Measurements of arterial-venous lactate, total ammonia, β-hydroxybutyrate, glucose, and L-alanine concentrations in the perfused tail-trunk assessed white muscle metabolite fluxes. Exhaustive exercise was fuelled primarily by creatine phosphate hydrolysis and glycolysis as indicated by 62, 71, and 85% decreases in ATP, creatine phosphate, and glycogen, respectively. White muscle lactate production during exercise caused a sustained increase (∼12 h post-exercise) in plasma lactate load and a short-lived increase (∼4 h post-exercise) in plasma metabolic acid load during recovery. Exhaustive exercise and recovery did not affect arterial PO2, PCO2, or PNH3 but the metabolic acidosis caused a decrease in arterial HCO3 - immediately after exercise and during the first 8 h recovery. During recovery, lactate was retained in the white muscle at higher concentrations than in the plasma despite increased lactate efflux from the muscle. Pyruvate dehydrogenase activity was very low in dogfish white muscle at rest and during recovery (0.53±0.15 nmol g wet tissue-1 min-1; n=40) indicating that lactate oxidation is not the major fate of lactate during post-exercise recovery. The lack of change in white muscle free-carnitine and variable changes in short-chain fatty acyl-carnitine suggest that dogfish white muscle does not rely on lipid oxidation to fuel exhaustive exercise or recovery. These findings support the notion that extrahepatic tissues cannot utilize fatty acids as an oxidative fuel. Furthermore, our data strongly suggest that ketone body oxidation is important in fuelling recovery metabolism in dogfish white muscle and at least 20% of the ATP required for recovery could be supplied by uptake and oxidation of β-hydroxybutyrate from the plasma.

Original languageEnglish
Pages (from-to)463-474
Number of pages12
JournalJournal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
Volume173
Issue number6
DOIs
StatePublished - Aug 1 2003

Fingerprint

Squalus acanthias
Metabolism
Muscle
muscle
exercise
metabolism
Recovery
Muscles
muscles
lactates
Lactic Acid
Dogfish
Plasmas
plasma
Hydroxybutyrates
oxidation
Oxidation
creatine
Phosphocreatine
Carnitine

Keywords

  • β-Hydroxybutyrate
  • Carbohydrate
  • Elasmobranch white muscle
  • Lactate
  • Lipid

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Environmental Science(all)
  • Physiology
  • Physiology (medical)

Cite this

Exercise and recovery metabolism in the pacific spiny dogfish (Squalus acanthias). / Richards, J. G.; Heigenhauser, G. J F; Wood, C. M.

In: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology, Vol. 173, No. 6, 01.08.2003, p. 463-474.

Research output: Contribution to journalArticle

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