Premium
Lactate fuels the human brain during exercise
Author(s) -
Quistorff Bjørn,
Secher Niels H.,
Van Lieshout Johannes J.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.08-106104
Subject(s) - medicine , endocrinology , epinephrine , glucose uptake , chemistry , carbohydrate metabolism , adrenergic receptor , receptor , insulin
The human brain releases a small amount of lactate at rest, and even an increase in arterial blood lactate during anesthesia does not provoke a net cerebral lactate uptake. However, during cerebral activation associated with exercise involving a marked increase in plasma lactate, the brain takes up lactate in proportion to the arterial concentration. Cerebral lactate uptake, together with glucose uptake, is larger than the uptake accounted for by the concomitant O 2 uptake, as reflected by the decrease in cerebral metabolic ratio (CMR) [the cerebral molar uptake ratio O 2 /(glucose+½ lactate)] from a resting value of 6 to <2. The CMR also decreases when plasma lactate is not increased, as during prolonged exercise, cerebral activation associated with mental activity, or exposure to a stressful situation. The CMR decrease is prevented with combined β 1 ‐ and β 2 ‐adrenergic receptor blockade but not with β 1 ‐adrenergic blockade alone. Also, CMR decreases in response to epinephrine, suggesting that a β 2 ‐adrenergic receptor mechanism enhances glucose and perhaps lactate transport across the blood‐brain barrier. The pattern of CMR decrease under various forms of brain activation suggests that lactate may partially replace glucose as a substrate for oxidation. Thus, the notion of the human brain as an obligatory glucose consumer is not without exceptions.—Quistorff, B., Secher, N. H., and Van Lieshout, J. J. Lactate fuels the human brain during exercise. FASEB J. 22, 3443–3449 (2008)