Document Detail

Gluconeogenesis in humans with induced hyperlactatemia during low-intensity exercise.
MedLine Citation:
PMID:  12604505     Owner:  NLM     Status:  MEDLINE    
We studied the role of lactate in gluconeogenesis (GNG) during exercise in untrained fasting humans. During the final hour of a 4-h cycle exercise at 33-34% maximal O(2) uptake, seven subjects received, in random order, either a sodium lactate infusion (60 micromol x kg(-1) x min(-1)) or an isomolar sodium bicarbonate infusion. The contribution of lactate to gluconeogenic glucose was quantified by measuring (2)H incorporation into glucose after body water was labeled with deuterium oxide, and glucose rate of appearance (R(a)) was measured by [6,6-(2)H(2)]glucose dilution. Infusion of lactate increased lactate concentration to 4.4 +/- 0.6 mM (mean +/- SE). Exercise induced a decrease in blood glucose concentration from 5.0 +/- 0.2 to 4.2 +/- 0.3 mM (P < 0.05); lactate infusion abolished this decrease (5.0 +/- 0.3 mM; P < 0.001) and increased glucose R(a) compared with bicarbonate infusion (P < 0.05). Lactate infusion increased both GNG from lactate (29 +/- 4 to 46 +/- 4% of glucose R(a), P < 0.001) and total GNG. We conclude that lactate infusion during low-intensity exercise in fasting humans 1). increased GNG from lactate and 2). increased glucose production, thus increasing the blood glucose concentration. These results indicate that GNG capacity is available in humans after an overnight fast and can be used to sustain blood glucose levels during low-intensity exercise when lactate, a known precursor of GNG, is available at elevated plasma levels.
Mark J Roef; Kees de Meer; Satish C Kalhan; Helma Straver; Ruud Berger; Dirk-Jan Reijngoud
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.     Date:  2003-02-25
Journal Detail:
Title:  American journal of physiology. Endocrinology and metabolism     Volume:  284     ISSN:  0193-1849     ISO Abbreviation:  Am. J. Physiol. Endocrinol. Metab.     Publication Date:  2003 Jun 
Date Detail:
Created Date:  2003-05-08     Completed Date:  2003-06-19     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  100901226     Medline TA:  Am J Physiol Endocrinol Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  E1162-71     Citation Subset:  IM    
Department of Pediatric Gastroenterology, VU University Medical Center, 1007 MB Amsterdam, The Netherlands.
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MeSH Terms
Acid-Base Equilibrium / physiology
Bicarbonates / pharmacology
Blood Glucose / metabolism
Body Composition / physiology
Body Water / metabolism
Body Weight / physiology
Exercise / physiology*
Gluconeogenesis / physiology*
Glycerol / metabolism
Lactates / blood*
Oxygen Consumption / physiology
Pyruvic Acid / metabolism
Triglycerides / blood
Grant Support
Reg. No./Substance:
0/Bicarbonates; 0/Blood Glucose; 0/Lactates; 0/Triglycerides; 127-17-3/Pyruvic Acid; 56-81-5/Glycerol

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