The effect of ethanol on the interrelationship of lactate and glucose metabolism was investigated in eight human volunteers. Lactate and glucose kinetics and intervconversion rates were determined by the sequential administration of L-(+) lactate-U-(14)C and glucose-1-(14)C over an 8 hr period. After a 12 hr fast, the glucose turnover and recycling rates were 94.0 +/-3.8 (SEM) and 13.7 +/-1.1 m...

The cell-to-cell lactate shuttle was introduced in 1984 and has been repeatedly supported by studies using a variety of experimental approaches. Because of its large mass and metabolic capacity, skeletal muscle is probably the major component of the lactate shuttle in terms of both production and consumption. Muscles exercising in a steady state are avid consumers of lactate, using most of the ...

Helicobacter pylori are Gram-negative, spiral-shaped microaerophilic bacteria etiologically related to gastric cancer. Lactate utilization has been implicated although no corresponding genes have been identified in the H. pylori genome. Here, we report that gene products of hp0137-0139 (lldEFG), hp0140-0141 (lctP), and hp1222 (dld) contribute to D- and L-lactate utilization in H. pylori. The th...

UNLABELLED Lactate is a key myocardial energy source. Lactate metabolism is altered in a variety of conditions, such as exercise and diabetes mellitus. However, to our knowledge, noninvasive quantitative measurements of myocardial lactate metabolism have never been performed because of the lack of an adequate radiotracer. In this study we tested L-3-(11)C-lactate ((11)C-lactate) as such a trace...

Once thought to be the consequence of oxygen lack in contracting skeletal muscle, the glycolytic product lactate is formed and utilized continuously under fully aerobic conditions. "Cell-cell" and "intracellular lactate shuttle" concepts describe the roles of lactate in the delivery of oxidative and gluconeogenic substrates, as well as in cell signalling. Examples of cell-cell shuttles include ...

Stereospecific Permeability of Rat BloodBrain Barrier to Lactic Acid • Blood and whole brain C and P activities were determined in hepatectomized rats one, two, five and ten minutes after intravenous (I.V.) injection of C-labeled L-lactate or D-lactate and P-labeled rat red blood cells. Whole brain homogenate C was corrected for blood "C and chemically partitioned into "C-lactate, CO2 and other...

The simultaneous release and uptake of lactate by the heart has been observed both in vivo and ex vivo; however, the pathways underlying these observations have not been satisfactorily explained. Consequently, the purpose of this study was to test the hypothesis that hearts release lactate from glycolysis while simultaneously taking up exogenous lactate. Therefore, we determined the effects of ...

BACKGROUND Around birth, myocardial substrate supply changes from carbohydrates before birth to primarily fatty acids after birth. Parallel to these changes, the myocardium is expected to switch from the use of primarily lactate before birth to fatty acids thereafter. However, myocardial lactate uptake and oxidation around birth has not been measured in vivo. METHODS AND RESULTS We measured m...

We evaluated the hypothesis that lactate shuttling helps support the nutritive needs of injured brains. To that end, we utilized dual isotope tracer [6,6-(2)H2]glucose, that is, D2-glucose, and [3-(13)C]lactate techniques involving arm vein tracer infusion along with simultaneous cerebral (arterial [art] and jugular bulb [JB]) blood sampling. Traumatic brain injury (TBI) patients with nonpenetr...