HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 103/4/1227    most recent 00027.2007v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Nielsen, H. B. Articles by Secher, N. H. Search for Related Content PubMed PubMed Citation Articles by Nielsen, H. B. Articles by Secher, N. H.

Hepatic lactate uptake versus leg lactate output during exercise in humans

Copenhagen Muscle Research Center, Departments of ¹Anesthesiology and ²Hepatology, Rigshospitalet, and ⁵August Krogh Institute, University of Copenhagen, ⁴Medical Department V, Aarhus University Hospital, Denmark, and ³Cellular and Molecular Laboratory, Baker Heart Research Institute, Melbourne, Australia

Submitted 1 January 2007 ; accepted in final form 18 July 2007

The exponential rise in blood lactate with exercise intensity may be influenced by hepatic lactate uptake. We compared muscle-derived lactate to the hepatic elimination during 2 h prolonged cycling (62 ± 4% of maximal O₂ uptake, O_2max) followed by incremental exercise in seven healthy men. Hepatic blood flow was assessed by indocyanine green dye elimination and leg blood flow by thermodilution. During prolonged exercise, the hepatic glucose output was lower than the leg glucose uptake (3.8 ± 0.5 vs. 6.5 ± 0.6 mmol/min; mean ± SE) and at an arterial lactate of 2.0 ± 0.2 mM, the leg lactate output of 3.0 ± 1.8 mmol/min was about fourfold higher than the hepatic lactate uptake (0.7 ± 0.3 mmol/min). During incremental exercise, the hepatic glucose output was about one-third of the leg glucose uptake (2.0 ± 0.4 vs. 6.2 ± 1.3 mmol/min) and the arterial lactate reached 6.0 ± 1.1 mM because the leg lactate output of 8.9 ± 2.7 mmol/min was markedly higher than the lactate taken up by the liver (1.1 ± 0.6 mmol/min). Compared with prolonged exercise, the hepatic lactate uptake increased during incremental exercise, but the relative hepatic lactate uptake decreased to about one-tenth of the lactate released by the legs. This drop in relative hepatic lactate extraction may contribute to the increase in arterial lactate during intense exercise.

cycling; glucose; liver blood flow

This article has been cited by other articles:

				B. Quistorff, N. H. Secher, and J. J. Van Lieshout Lactate fuels the human brain during exercise FASEB J, October 1, 2008; 22(10): 3443 - 3449. [Abstract] [Full Text] [PDF]

				S. Volianitis, A. Fabricius-Bjerre, A. Overgaard, M. Stromstad, M. Bjarrum, C. Carlson, N. T. Petersen, P. Rasmussen, N. H. Secher, and H. B. Nielsen The cerebral metabolic ratio is not affected by oxygen availability during maximal exercise in humans J. Physiol., January 1, 2008; 586(1): 107 - 112. [Abstract] [Full Text] [PDF]