Modulation of ATP production by oxygen in obstructive lung disease as assessed by 31P-MRS

E. T. Mannix, M. D. Boska, P. Galassetti, G. Burton, F. Manfredi, M. O. Farber

Research output: Contribution to journalArticlepeer-review

54 Scopus citations

Abstract

Inadequate O2 supply may impair intramuscular oxidative metabolism and O2 availability may modulate ATP production within exercising muscle. Therefore, we studied ATP flux from anaerobic glycolysis, the creatine kinase reaction, and oxidative phosphorylation using 31P-magnetic resonance spectroscopy kinetic data collected during exercise. We examined six chronic obstructive pulmonary disease (COPD) patients with severe hypoxemia (group 1), seven COPD patients with mild hypoxemia (group 2), and seven healthy control subjects. Exercise (90-s isometric contraction of the gastrocnemius- soleus muscle group, 40% of max) was performed on room air for all subjects; for COPD patients, it was repeated during supplemental O2 at identical power outputs, with 60-min rest between the two sets. In group 1 (air vs. O2), oxidative phosphorylation ATP production was lower (P < 0.05), anaerobic glycolysis ATP production was higher (P < 0.05), and anaerobic glycolysis plus creatine kinase ATP production tended to be higher (P = 0.06). In group 2, no differences were observed across conditions. Assuming that mitochondrial size, density, function, and redox state were not affected by acute changes in the inspired O2 fraction, reduced O2 availability is the remaining factor that could have limited oxidative ATP production during hypoxemia. In conclusion, in severely hypoxemic COPD patients, O2 availability apparently limits intramuscular oxidative metabolism because acute hypoxemia increases anaerobic and decreases aerobic ATP production.

Original languageEnglish (US)
Pages (from-to)2218-2227
Number of pages10
JournalJournal of Applied Physiology
Volume78
Issue number6
DOIs
StatePublished - 1995

Keywords

  • chronic obstructive pulmonary disease
  • energy metabolism
  • hypoxemia
  • phosphorus-31 magnetic resonance spectroscopy

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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