Laktátdehydrogenáza

Laktátdehydrogenáza, often abbreviated as LDH, is an enzyme found in many tissues throughout the body, primarily in the cytoplasm of cells. Its main function is to catalyze the reversible conversion of lactate to pyruvate and back. This reaction is a crucial part of cellular respiration, particularly under anaerobic conditions when oxygen is scarce. During anaerobic metabolism, cells produce lactate as a byproduct, and LDH helps to regenerate NAD+ from NADH, which is essential for glycolysis to continue producing ATP.

Elevated levels of LDH in the blood are not specific to any single disease but can indicate tissue damage or inflammation. When cells are injured or die, their contents, including LDH, are released into the bloodstream. Therefore, LDH is often used as a general marker for cellular damage, and its levels can be monitored in various conditions such as heart attack, liver disease, muscle injury, and certain cancers.

The measurement of LDH in serum is a common laboratory test. While a high LDH level suggests tissue damage, further investigations are usually required to determine the specific cause. Different isoenzymes of LDH exist, each with a slightly different structure and distribution in the body. Measuring these isoenzymes can sometimes provide more specific information about the location of the tissue damage, for example, LDH-1 is predominantly found in the heart and red blood cells, while LDH-5 is more concentrated in the liver and skeletal muscle.