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Human brain is oxidizing substantial quantities of lactate under basal and hyperlactatemic conditions
Author(s) -
Rasmussen Peter,
Van Hall Gerrit,
Gam Christiane,
Jans Øivind,
Zaar Morten,
Secher Niels Henry,
Quistorff Bjørn,
Nielsen Henning Bay
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/fasebj.22.2_supplement.96
Subject(s) - hyperlactatemia , in vivo , chemistry , medicine , basal (medicine) , endocrinology , lactic acid , anaerobic exercise , metabolism , biochemistry , biology , physiology , insulin , genetics , microbiology and biotechnology , bacteria
Neurons have been suggested to utilize lactate as their main energy substrate, the lactate originating from astrocytes and the circulation. Indeed, human cerebral lactate uptake has been observed, however, its fate unknown. Therefore, the aim of this study was to determine in vivo human cerebral lactate metabolism. For this we measured in vivo cerebral lactate turnover and oxidation in 6 healthy individuals with a combination of tracer dilution methodology ([1‐ 13 C]lactate) and arterial minus right internal jugular venous differences during 2 hours at basal condition (Bas) and during 90 min of ‘cold’ lactate infusion (36 μmol.kg −1 bw.min −1 ) (LacInf), causing lactate levels to increase from 0.86±0.08 to 3.94±0.35 mmol.l −1 . The cerebral lactate utilization changed from a net lactate release of 0.06±0.01 (Bas) to an uptake of 0.14±0.05 mmol.min −1 during LactInf, with a concomitant decrease in net glucose uptake. Cerebral [1‐ 13 C]lactate uptake was for 100±24% (Bas) and 86±15% (LactInf) recovered as 13 CO 2 , and not different. The contribution of systemic lactate uptake and subsequent oxidation to cerebral energy expenditure was 7.7±2.1 and 19±4.2% for Bas and LactInf, respectively. In conclusion, we have shown that systemic lactate is taken up and oxidized by the human brain and that it is a quantitatively important substrate under basal and hyperlactatemia conditions.