lactate dehydrogenase

lactate dehydrogenase

n. Abbr. LDH

Any of a class of enzymes found in the liver, kidneys, striated muscle, and heart muscle that catalyze the reversible conversion of pyruvate and lactate.

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lactate dehydrogenase (LDH),

an enzyme that is found in the cytoplasm of almost all body tissues, where its main function is to catalyze the oxidation of l-lactate to pyruvate. It is assayed as a measure of anaerobic carbohydrate metabolism and as one of several serum indicators of myocardial infarction and muscular dystrophies. Serum levels of LDH usually rise 12 to 18 hours after myocardial cell necrosis. See also aspartate aminotransferase, CK isoenzyme fraction, Duchenne's muscular dystrophy.

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lactate dehydrogenase (LD, LDH) [lak´tāt de-hi´dro-jĕ-nās]

an enzyme that catalyzes the interconversion of lactate and pyruvate. It is widespread in tissues and is particularly abundant in kidney, skeletal muscle, liver, and myocardium. It has five isoenzymes denoted LD₁ to LD₅. The “flipped” pattern in which the serum LD₁ level is greater than the LD₂ level is indicative of an acute myocardial infarction. This pattern occurs within 12 to 24 hours after the attack.

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lactate dehydrogenase

(lak´tāt dē´hīdroj´nās´),
n an enzyme found in the cytoplasm of almost all body tissues, where its main function is to catalyze the oxidation of L-lactate to pyruvate.

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lactate

1. any salt of lactic acid or the anion of lactic acid.

2. to secrete milk.

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lactate dehydrogenase

called also LD, LDH; see lactate dehydrogenase.

lactate dehydrogenase test

a high level in milk used as an indicator of the presence of mastitis in the quarter.

exercise blood lactate

exercise by a horse begins aerobically without any elevation of blood lactate levels; exercise at faster levels is eventually performed anaerobically and blood lactate levels rise steeply.

lactate shuttle

the production of lactate in resting muscle where adequate oxygenation is available; represents a mechanism for conserving glucose absorbed from the gut by allowing it to be converted to lactate by skeletal muscle and later used for work or transferred to the liver for glycogen synthesis.

lactate T_m

maximal tubular concentration of lactate.

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lactate dehydrogenase

Cardiology An oxidoreductase present in the cytoplasm of all cells that catalyze Lactate + NAD+ ↤ Pyruvate + NADH + H+, the equilibrium of which favors lactate + NAD+ at neutral pH; LD₁ is classically ↑ in acute MI, peaking by post-infarct day 4, and associated with a flip in normal ratio of LD₁ and LD₂. See Flipped LD, LD_{6. Cf CK-MB, Troponin I, Troponin T.}