1. [2-(3)H,U-(14)C]- or [3-(3)H,U-(14)C]-Lactate was administered by infusion or bolus injection to overnight-starved rats. Tracer lactate was injected or infused through indwelling cannulas into the aorta and blood was sampled from the vena cava (A-VC mode), or it was administered into the vena cava and sampled from the aorta (V-A mode). Sampling was continued after infusion was terminated to ...

Glucose is the major energetic substrate for the brain but evidence has accumulated during the last 20 years that lactate produced by astrocytes could be an additional substrate for neurons. However, little information exists about this lactate shuttle in vivo in activated and awake animals. We designed an experiment in which the cortical barrel field (S1BF) was unilaterally activated during in...

The characteristics of lactate transport in brush-border membrane vesicles isolated from normal human full-term placentas were investigated. Lactate transport in these vesicles was Na+-independent, but was greatly stimulated when the extravesicular pH was made acidic. In the presence of an inwardly directed H+ gradient ([H+]o greater than [H+]i), transient uphill transport of lactate could be d...

Rates of formation and dissociation of an abortive ternary complex between lactate dehydrogenase isozymes from various mammalian tissues, NADf, and pyruvate were studied utilizing stopped-flow spectrofluorometry. Formation of the complex was accompanied by a decrease in protein fluorescence at 340 rnp and a loss of lactate dehydrogenase activity. Rates of formation of an abortive lactate dehydr...

The antimicrobial effect of L-lactate was much greater than that of D-lactate over a range of concentrations for Escherichia coli O157 and non-O157 strains. Despite this, the intracellular pHs and membrane potentials of L-lactate- and D-lactate-treated cells were similar, suggesting that these factors are not involved in the antimicrobial action of L-lactate.

Lactate acts as a 'buffer' between glycolysis and oxidative metabolism. In addition to being exchanged as a fuel by the monocarboxylate transporters (MCTs) between cells and tissues with different glycolytic and oxidative rates, lactate may be a 'volume transmitter' of brain signals. According to some, lactate is a preferred fuel for brain metabolism. Immediately after brain activation, the rat...

The purpose of this study was to examine fuel used during muscle glycogenesis in rainbow trout Oncorhynchus mykiss using an in vitro muscle slice preparation to test the hypothesis that intracellular lactate is the major glycogenic substrate and the muscle relies upon extracellular substrates for oxidation. Fish were exhaustively exercised to reduce muscle glycogen content, muscle slices were t...

Lactate is shuttled between and inside cells, playing metabolic and signaling roles in healthy tissues. Lactate is also a harbinger of altered metabolism and participates in the pathogenesis of inflammation, hypoxia/ischemia, neurodegeneration and cancer. Many tumor cells show high rates of lactate production in the presence of oxygen, a phenomenon known as the Warburg effect, which has diagnos...

Lactobacillus plantarum is a lactic acid bacterium that produces d- and l-lactate using stereospecific NAD-dependent lactate dehydrogenases (LdhD and LdhL, respectively). However, reduction of glycolytic pyruvate by LdhD is not the only pathway for d-lactate production since a mutant defective in this activity still produces both lactate isomers (T. Ferain, J. N. Hobbs, Jr., J. Richardson, N. B...

Active neurons have a high demand for energy substrate, which is thought to be mainly supplied as lactate by astrocytes. Heavy lactate dependence of neuronal activity suggests that there may be a mechanism that detects and controls lactate levels and/or gates brain activation accordingly. Here, we demonstrate that orexin neurons can behave as such lactate sensors. Using acute brain slice prepar...