1156 During exercise, glycolysis occurs simultaneously with numerous other cellular processes and is thus difficult to quantify. During ischemic recovery from ischemic exercise, however, flux through the glycolytic pathway may be observed in isolation and measured directly. The purposes of this study were (1) to determine whether the initial post-exercise glycolytic flux is an accurate measure of the flux during exercise and (2) to characterize the time course of changes in flux at the start and end of exercise. Blood flow to subjects' dorsiflexor muscles was stopped via the inflation of a pneumatic cuff wrapped around the thigh. After intracellular oxygen stores were depleted, subjects performed rapid voluntary dorsiflexions while phosphorus-31 nuclear magnetic resonance spectra of the active muscle group were acquired. Glycolytic fluxes were computed from the observed changes in muscle pH and [phosphocreatine]. The flux was essentially unchanged from its basal level after 12 contractions but rose to 43% of its eventual steady-state rate by the 30th contraction. Conversely, post-exercise flux was initially equal to the flux calculated during exercise but declined to resting levels within 30 seconds of the end of exercise. We conclude that (1) initial post-exercise glycolytic flux is a direct, accurate measure of flux during voluntary exercise and that (2) there is a latency in the glycolytic response to changes in muscle activity. Supported by NIH AR42928 and AR45184. G.J.C. is the recipient of an NSF predoctoral fellowship.
No takes yet. Share an insight, caveat, or question.
Crowther et al. (1999) studied this question.