Hepatic lactate uptake versus leg lactate output during exercise in humans
Copenhagen Muscle Research Center, Departments of 1 Anesthesiology and 2 Hepatology, Rigshospitalet, and 5 August Krogh Institute, University of Copenhagen, 4 Medical Department V, Aarhus University Hospital, Denmark, and 3 Cellular and Molecular Laboratory, Baker Heart Research Institute, Melbourne...
Saved in:
Published in | Journal of applied physiology (1985) Vol. 103; no. 4; pp. 1227 - 1233 |
---|---|
Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Bethesda, MD
Am Physiological Soc
01.10.2007
American Physiological Society |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Copenhagen Muscle Research Center, Departments of 1 Anesthesiology and 2 Hepatology, Rigshospitalet, and 5 August Krogh Institute, University of Copenhagen, 4 Medical Department V, Aarhus University Hospital, Denmark, and 3 Cellular 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 O 2 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
Address for reprint requests and other correspondence: H. Bay Nielsen, Dept. of Anesthesia 2041, Rigshospitalet, Blegdamsvej 9, 2100 København Ø, Denmark (e-mail: hbay{at}vip.cybercity.dk ) |
---|---|
Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 8750-7587 1522-1601 |
DOI: | 10.1152/japplphysiol.00027.2007 |