gastric juice gamma-glutamyltransferase

Gammaglutamyltransferase (γ-GT or GGT) is a peptide transferase that catalyzes the transfer of γ-glutamyl. Its natural donor is glutathione (GSH), and the receptor is L-amino acid. γ-GT has a molecular weight of 90 kD, and its main function in the body is to participate in the “γ-glutamyl cycle”, which is related to the transport of amino acids through the cell membrane and the regulation of GSH levels. The contents of γ-GT in various organs of the human body are kidney, prostate, pancreas, liver, cecum and brain. The γ-GT activity in serum mainly comes from the liver and bile system, and has carcinoembryogenic properties. However, in kidney disease, the activity of the enzyme in the serum is not significantly increased, which may be related to the discharge of urine. Therefore, γ-GT is mainly used for the auxiliary diagnosis of digestive diseases. Basic Information Specialist classification: Digestive examination classification: biochemical examination Applicable gender: whether men and women apply fasting: fasting Tips: Keep a normal mindset. Normal value Fasting gastric juice <8U. Clinical significance >8U can be seen in gastric cancer. High results may be diseases: precautions for gastric cancer Colorimetric method: 1. The type of buffer is different, and the optimum pH of the enzyme reaction is also different. Tris buffer is most suitable. 2. The free α-naphthylamine in the substrate buffer is unstable and has an inhibitory effect on the enzyme. Therefore, attention should be paid to the influence of temperature during preparation. If the absorbance of the reagent blank tube is >0.08, L-γ-glutamyl-α-naphthylamine should be recrystallized to remove free α-naphthylamine. 3, 1g / L sodium nitrite solution is unstable, should be formulated once a week. 4, the specimen is easy to use serum or body fluids, and EDTA-Na2 (1mg / ml) anticoagulant plasma, other anticoagulants can affect the results. 5, GGT is relatively stable, placed at room temperature for 2 days, there is no change in enzyme activity at 4 °C for 1 week, but all inactivation at 65 °C for 1 min. Inspection process Method of collecting gastric juice: Before collecting gastric juice, fasting, banned drugs, and smoking bans for more than a few hours. In the morning, the doctor will sterilize (cooked) the stomach tube into the stomach through the nose or mouth, and reach the stomach bend at a depth of 50-55 cm. Mucus pool; then use a 50 ml syringe to the stomach tube to aspirate the gastric juice (or continue to attract with a negative pressure pump), after filling, inject into the container, and then take the tube to continue pumping; the patient can change position during the collection process , side, prone and sitting position), try to suck the liquid in the stomach as much as possible; after the tube is removed, record the amount of gastric juice extracted, and label it on the container for inspection. Verification method: Use the colorimetric method. 1. Buffer (pH 8.0, 25 ° C): Weigh 9.1 g of Tris, 3.96 g of glyphosate, dissolve in 400 ml of distilled water, add distilled water to 500 ml, add 1 ml of chloroform, and store in a refrigerator. 2, substrate buffer (pH 7.8 ~ 7.9): weigh 217mg of L-γ-glutamyl-α-naphthylamine (no crystal water, MW272.3), placed in a small beaker, add 1mol / LHCl about 4ml After completely dissolved, add 90 ml of the above Tris diglycoside buffer, adjust to pH 8.0 ± 0.1 with 1 mol/L HCl at 25 ° C, then add water to 100 ml, and store in a refrigerator. 3, 2g / L p-aminobenzenesulfonic acid acetic acid solution (containing 20% ​​acetic acid), stored in the refrigerator. 4, 1g / L sodium nitrite aqueous solution, stored in the refrigerator. 5, color reagent: take 4 liquid 4ml, add 3 liquid 100ml and mix, the same day. Not suitable for the crowd Gastric perforation is prohibited in patients with gastric perforation. Adverse reactions and risks Generally no complications and harm.