Document Detail


Metabolic and cardiorespiratory responses to "the lactate clamp".
MedLine Citation:
PMID:  12376315     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
To evaluate the hypothesis that precursor supply limits gluconeogenesis (GNG) during exercise, we examined training-induced changes in glucose kinetics [rates of appearance (R(a)) and disappearance (R(d))], oxidation (R(ox)), and recycling (R(r)) with an exogenous lactate infusion to 3.5-4.0 mM during rest and to pretraining 65% peak O(2) consumption (VO(2 peak)) levels during exercise. Control and clamped trials (LC) were performed at rest pre- (P(R)R, P(R)R-LC) and posttraining (P(O)R, P(O)R-LC) and during exercise pre- (P(R)E(X)) and posttraining at absolute (P(O)A(B), P(O)A(B)-LC) and relative (P(O)R(L), P(O)R(L)-LC) intensities. Glucose R(r) was not different in any rest or exercise condition. Glucose R(a) did not differ as a result of LC. Glucose R(ox) was significantly decreased with LC at P(O)R (0.38 +/- 0.03 vs. 0.56 +/- 0.04 mg. kg(-1). min(-1)) and P(O)A(B) (3.82 +/- 0.51 vs. 5.0 +/- 0.62 mg. kg(-1). min(-1)). Percent glucose R(d) oxidized decreased with all LC except P(O)R(L)-LC (P(R)R, 32%; P(R)R-LC, 22%; P(O)R, 27%; P(O)R-LC, 20%; P(O)A(B), 95%; P(O)A(B)-LC, 77%), which resulted in a significant increase in oxidation from alternative carbohydrate (CHO) sources at rest and P(O)A(B). We conclude that 1) increased arterial [lactate] did not increase glucose R(r) measured during rest or exercise after training, 2) glucose disposal or production did not change with increased precursor supply, and 3) infusion of exogenous CHO in the form of lactate resulted in the decrease of glucose R(ox).
Authors:
Benjamin F Miller; Jill A Fattor; Kevin A Jacobs; Michael A Horning; Sang-Hoon Suh; Franco Navazio; George A Brooks
Related Documents :
2022575 - Carbohydrate metabolism during intense exercise when hyperglycemic.
3728665 - Leg glucose uptake during maximal dynamic exercise in humans.
3536495 - Comparison of the effects of pre-exercise feeding of glucose, glycerol and placebo on e...
2689365 - Protein and energy metabolism during prolonged exercise in trained athletes.
10774875 - Quadriceps-hamstring emg activity during functional, closed kinetic chain exercise to f...
1566925 - Human thermoregulatory responses during heat exposure after artificially induced sunburn.
Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  American journal of physiology. Endocrinology and metabolism     Volume:  283     ISSN:  0193-1849     ISO Abbreviation:  Am. J. Physiol. Endocrinol. Metab.     Publication Date:  2002 Nov 
Date Detail:
Created Date:  2002-10-11     Completed Date:  2002-11-08     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100901226     Medline TA:  Am J Physiol Endocrinol Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  E889-98     Citation Subset:  IM    
Affiliation:
Department of Integrative Biology, University of California, Berkeley, California 94720, USA.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Adolescent
Adult
Blood Glucose / metabolism*
Blood Pressure / drug effects,  physiology*
Energy Metabolism / drug effects,  physiology
Fatty Acids, Nonesterified / blood
Glycerol / blood
Heart Rate / drug effects,  physiology*
Homeostasis / drug effects,  physiology
Humans
Insulin / blood
Lactic Acid / blood,  pharmacokinetics*
Male
Oxygen Consumption / physiology
Physical Exertion / drug effects,  physiology*
Respiration
Rest / physiology
Weight Loss / physiology
Grant Support
ID/Acronym/Agency:
AR-42906/AR/NIAMS NIH HHS
Chemical
Reg. No./Substance:
0/Blood Glucose; 0/Fatty Acids, Nonesterified; 11061-68-0/Insulin; 50-21-5/Lactic Acid; 56-81-5/Glycerol

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Potentiation of insulin secretion by phorbol esters is mediated by PKC-alpha and nPKC isoforms.
Next Document:  Effect of endotoxin on expression of TNF receptors and transport of TNF-alpha at the blood-brain bar...