To evaluate the potential role of mitochondrial lactate dehydrogenase (LDH) in tissue lactate clearance and oxidation in vivo, isolated rat liver, cardiac, and skeletal muscle mitochondria were incubated with lactate, pyruvate, glutamate, and succinate. As well, alpha-cyano-4-hydroxycinnamate (CINN), a known monocarboxylate transport inhibitor, and oxamate, a known LDH inhibitor were used. Mito...

To study the role of muscle mass and muscle activity on lactate and energy kinetics during exercise, whole body and limb lactate, glucose, and fatty acid fluxes were determined in six elite cross-country skiers during roller-skiing for 40 min with the diagonal stride (Continuous Arm + Leg) followed by 10 min of double poling and diagonal stride at 72-76% maximal O(2) uptake. A high lactate appe...

Mechanisms of hepatic lactate uptake were studied in the gulf toadfish, Opsanus beta by following the accumulation of [C]lactate by isolated hepatocytes in vitro. Uptake rates were linear for up to 5 s at external lactate concentrations of 1 and 20mmoll~'. 5-s uptake rates for several concentrations in the physiological range (i.e. 0-2-20mmoll") yielded a linear double reciprocal plot (l/v vs l...

Lactic acid is produced as an end product of glycolysis in rainbow trout white muscle following exhaustive exercise. The metabolically produced lactic acid causes an intramuscular acidosis that must be cleared, either via net transport out of the muscle or by conversion to glycogen, thereby replenishing the muscle energy store. Trout muscle has been shown to retain lactate and utilise it as a s...

Rainbow trout ( Oncorhynchus rnykiss ) retain the majority of lactate produced during exhaustive exercise within the white muscle. Previous studies have suggested that this retention is partiaiiy via a reuptake of released lactate. The purpose of this work was to study lactate uptake using trout white muscle sarcolemmai vesicles. Through modifications to the original mammalian giant vesicle tec...

This study was undertaken to quantitatively account for the metabolic disposal of lactate in skeletal muscle exposed to an elevated lactate concentration during rest and mild-intensity contractions. The gastrocnemius plantaris muscle group (GP) was isolated in situ in seven anesthetized dogs. In two experiments, the muscles were perfused with an artificial perfusate with a blood lactate concent...

In all vertebrates, including humans, the L-lactate form is by far the most abundant and pathophysiologically significant, and it is this form that is specifically measured by the lactate sensors in blood gas analyzers and indeed all routine methods used to measure lactate in the clinical laboratory. The main focus of this brief review is physiological and pathological aspects that distinguish ...