| Isotopic determination of glycolytic flux during intense exercise in humans. | |
| | |
MedLine Citation:
|
PMID: 7759416 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
We used a new stable isotope tracer approach incorporating muscle intracellular lactate enrichment to determine the flux of glucose/glucosyl toward lactate [i.e., nonoxidized pyruvate (Pyr) production (Pyrno)] in moderately trained cyclists exercising at approximately 80% (259 +/- 16 W; n = 6) and approximately 100% (341 +/- 9 W; n = 8) maximal O2 uptake (VO2max). Primed constant infusions of [6,6-2H2]glucose and [13C]lactate or [13C]Pyr tracers were given, and rapid achievement of plateau was obtained during exercise by increasing the infusion rates at exercise onset to correspond with expected increases in production. The accumulated O2 deficit was simultaneously determined over the 1st 3 min of exercise as an indirect means of quantifying glycolytic flux for comparison with our tracer-determined values and was significantly greater at the higher intensity (38 +/- 3 vs. 30 +/- 3 ml O2.kg-1.3 min-1; P < 0.02). Pyrno was also significantly higher (6.38 +/- 0.91 vs. 4.38 +/- 0.65 mmol.kg-1.min-1 over 3 min at 100 and 80% VO2max, respectively). The blood lactate rate of appearance at approximately 100% VO2max (828 +/- 69 mumol.kg-1.min-1) represented a higher percentage of Pyr rate of appearance (RaPyr; 31 +/- 3%) than that at approximately 80% VO2max (416 +/- 36 mumol.kg-1.min-1; 22 +/- 2%; P < 0.02). Although only approximately 27 +/- 2% of RaPyr was oxidized, this provided 78 +/- 2% of the total energy demand during the 1st 3 min of exercise at either intensity. Our new method provided values for Pyrno that were in the expected range and were highly correlated with respective accumulated O2 deficit values (r = 0.87, P < 0.0001). In conclusion, our new tracer method appears to be valid for the measurement of RaPyr and Pyrno during high-intensity exercise lasting even < 10 min. |
| | |
Authors:
|
B D Williams; I Plag; J Troup; R R Wolfe |
Related Documents
:
|
10924076 - Niacin protects the isolated heart from ischemia-reperfusion injury. 9721746 - Age-related differences in the effect of dichloroacetate on postischemic lactate and ac... 20975106 - Effects of a mineral antioxidant complex on clinical safety, body water, lactate respon... 11739096 - Increases in muscle mct are associated with reductions in muscle lactate after a single... 16968346 - Becker's rational addiction theory: an empirical test with price elasticities for disti... 19251876 - The role of mood disorders in exercise-induced cardiovascular reactivity. |
Publication Detail:
|
Type: Clinical Trial; Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
|
Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 78 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 1995 Feb |
Date Detail:
|
Created Date: 1995-06-29 Completed Date: 1995-06-29 Revised Date: 2007-11-14 |
Medline Journal Info:
|
Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: UNITED STATES |
Other Details:
|
Languages: eng Pagination: 483-90 Citation Subset: IM |
Affiliation:
|
Metabolism Unit, Shriners Burns Institute, Galveston, Texas 77550-2725, USA. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Adult Anaerobiosis / physiology Blood Glucose / metabolism Energy Metabolism / physiology Exercise / physiology* Glycolysis / physiology* Humans Lactates / metabolism Lactic Acid Male Oxygen Consumption / physiology Pyruvates / metabolism Pyruvic Acid Regression Analysis |
| Grant Support | |
ID/Acronym/Agency:
|
DK-38010/DK/NIDDK NIH HHS |
| Chemical | |
Reg. No./Substance:
|
0/Blood Glucose; 0/Lactates; 0/Pyruvates; 127-17-3/Pyruvic Acid; 50-21-5/Lactic Acid |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: NG-nitro-L-arginine and phenylephrine have similar effects on the vascular waterfall in the canine h...
Next Document: Diaphragmatic failure during group B streptococcal sepsis in piglets: the role of thromboxane A2.