Detection and Analysis of Lactate Dehydrogenase and Isozyme

Lactate dehydrogenase is a glycolytic enzyme. Lactate dehydrogenase exists in the cytoplasm of all tissues and cells of the body, among which the content is higher in the kidney. Lactate dehydrogenase is an enzyme that can catalyze the dehydrogenation of lactate to pyruvate, and it exists in almost all tissues. There are five forms of isozymes, namely LDH-1 (H4), LDH-2 (H3M), LDH-3 (H2M2), LDH-4 (HM3) and LDH-5 (M4), which can be separated by electrophoresis . The distribution of LDH isoenzymes has obvious tissue specificity, so it can be used to diagnose diseases based on its tissue specificity. LDH2 in normal human serum> LDH1. If myocardial enzymes are released into the blood, LDH1>LDH2, this index can be used to observe and diagnose myocardial diseases.

Desheng Enzyme

Normal range: serum 135.0～215.0U/L;

Urine 560～2050U/L;

The content of cerebrospinal fluid is 1/10 of that of serum.

Clinical significance:

(1) After the onset of acute myocardial infarction, the activities of LDH1 and LDH2 in the early serum are both increased, but the increase of LDH1 is earlier and more obvious, resulting in an increase in the ratio of LDH1/LDH2.

(2) LDH5 will increase during hepatitis, acute liver cell injury and skeletal muscle injury.

(3) LDH1 can also increase in diseases such as active rheumatic heart disease, acute viral myocarditis, hemolytic anemia, and renal necrosis.

Lactate dehydrogenase (LDH) in human tissues can be separated by electrophoresis in five isoenzyme zones, which are named LDH1, LDH2, LDH3, LDH4, LDH5 according to their electrophoretic mobility. Different tissues have different distributions of lactate dehydrogenase isoenzymes and have obvious tissue specificity. Human myocardium, kidney and red blood cells have the most LDH1 and LDH2, skeletal muscle and liver have the most LDH4 and LDH5, while lung, spleen, and pancreas have the most LDH1 and LDH2. Among tissues such as thyroid, adrenal gland and lymph node, LDH3 is the most. Later, LDHx was found in the testis and sperm, and its electrophoretic mobility was between LDH4 and LDH5. LDH is composed of two types of subunits, H (cardiomyocyte type) and M (skeletal muscle type), which form LDH1 (H4), LDH2 (H3M), LDH3 (H2M2), LDH4 (HM3), LDH5 (M4), respectively.

Reasons for high lactate dehydrogenase:

1. When the condition of a hepatitis B virus carrier deteriorates into a hepatitis B patient, some liver cells are damaged, and the levels of LDH4 and LDH5 in the serum will increase to varying degrees.

2. The treatment of hepatitis B, especially improper medication, can cause nephrotoxicity when taking the same medicine for a long time. When nephrotoxicity occurs, the content of lactate dehydrogenase in the serum will rise rapidly.

3. If hepatitis B is not treated properly and actively, it will cause serious abnormalities in liver metabolism when it develops to a certain extent, leading to kidney failure, which will also cause the content of lactate dehydrogenase to increase.

4. Pulmonary infarction, pernicious anemia, shock and tumor metastasis caused by pleural and ascites fluid can cause high lactate dehydrogenase

Reasons for low lactate dehydrogenase:

Lactate dehydrogenase exists in the cytoplasm of all tissues and cells of the body, among which the content is higher in the kidney. The normal range of serum lactate dehydrogenase is 100-300 U/L. When lactate dehydrogenase is low, the common causes are as follows:

1. Errors occurred during the inspection;

2. Endocrine disorders;

3. Too tired, poor sleep, bad mood, etc.

Low lactate dehydrogenase is generally not very serious and can be recovered after conditioning. However, if the lactate dehydrogenase is too high, attention should be paid. Because of pulmonary infarction, pernicious anemia, shock and tumor metastasis caused by pleural and ascites fluid, it will cause high lactate dehydrogenase.