secretin

Secretin is a digestive tract hormone (also known as secretin, pancreatin) released from the duodenal mucosal S cells and S cells dispersed in the jejunum (mainly the upper end). The secretin is an alkaline. The polypeptide consists of 27 amino acids, and has the same amino acid sequence of 9, 13 and 14 amino acid sequences as gastric inhibitory peptide, vasoactive intestinal peptide and glucagon, respectively. It is suggested that they evolved from the same hormone ancestor, so the four peptides are grouped together, called the pancreatic hormone family. Secretin is mainly eliminated by the kidneys. Gastric acid is the most important physiological factor that stimulates the release of pancreatin. The pH threshold for stimulating its release is 4.5, and other factors such as bile, sodium cholate and fat, calcium ions, alcohol, etc., stimulate the rise of pancreatin. The secretin has the following physiological effects 1 strongly stimulates the exocrine glands of the pancreas to secrete water and sodium bicarbonate. 2 stimulate bile secretion. 3 inhibit gastrin release and gastric acid secretion, inhibit local release of somatostatin. 4 inhibit gastrointestinal motility, and delay the emptying of gastric juice and solid food, enhance the gallbladder contraction of cholecystokinin. Basic Information Specialist classification: growth and development examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Tips: According to the nutritional status of the whole body, milk, eggs, fruits, soy milk, etc. are given in the meal. Normal value (4.4 ± 0.38) μg / L. Clinical significance A variety of diseases can affect the level of serum glucagon. 1. The levels of pancreatic hormone in the three cases of duodenal ulcer, Zhuo-Eye syndrome and advanced renal failure with increased gastric acid secretion were significantly increased. The concentration of secretin in patients with increased gastric acid secretion was (6.9±0.64) pg/ml, and the fasting plasma secretin level in Zhuo-Ai syndrome patients was higher than 15pg/ml. 2. Drinkers (including general drinking) can cause an increase in the release of immunologically active secretin. 3, insufficient secretion of secretin, resulting in strong alkaline pancreatic juice is not enough to neutralize the stomach acid into the duodenum, forming an ulcer. Therefore, in some patients with duodenal ulcer, the secretion of pancreaticin is less than normal. 4, celiac disease and "colon intestinal mucosal colonization" enteritis, jejunal finger villi disappear, surface mucosa atrophy, intestinal mucosal endocrine cell function decline, blood levels of pancreaticin decreased, can not stimulate the pancreas to secrete a large amount of bicarbonate, can not Neutralizes the stomach acid into the duodenum, so it is often accompanied by jejunal ulcers. The result is low, the disease may be high: the result of pediatric celiac disease is high. Possible diseases: precautions for duodenal ulcer The release of gastrin is affected by the excitability of the vagus nerve, and is also stimulated by food stimulation, gastric pyloric sinus expansion, and humoral factors. The pH of the gastrointestinal contents has a great influence on the release of gastrin. Inspection process The method is divided into three steps, namely antigen-antibody reaction, B and F separation, and radioactivity determination. 1. Antigen and antibody reaction: The specimen (non-labeled antigen), labeled antigen and antiserum are sequentially dosed into a small test tube, and allowed to stand at room temperature (15-30 ° C) for 24 hours to fully compete for binding. 2, B, F separation: a variety of separation techniques, commonly used precipitation method. 1 second antibody precipitation method: also known as diabody method, after the test antigen specifically reacts with the first antibody, the corresponding second antibody is added, so that the formed antigen-first antibody-second antibody complex is co-precipitated. The labeled antigen B is separated from the free antigen F by centrifugation. This method is a specific precipitation, complete separation, low non-specific binding. However, the amount of the second antibody is large and the cost is high. In addition, the serum concentration and the presence or absence of anticoagulants can affect the results to some extent. 2 Polyethylene glycol (PEG) precipitation method: the protein is in an isoelectric point state, and the hydration layer is destroyed to cause protein precipitation. The advantage of this method is that PEG is convenient to prepare, inexpensive, and rapid to separate. The disadvantage is that there are many non-specific precipitates and the separation is incomplete. 3Second antibody-polyethylene glycol precipitation method: This method not only has the advantage of rapid precipitation of PEG method, but also maintains the effect of specific precipitation of second antibody, reduces the amount of second antibody, and reduces the concentration of PEG, so that non-specific precipitation Reduced material. 4 Activated carbon adsorption method: the free part of small molecules is adsorbed by the surface activity of activated carbon. For example, a layer of dextran is coated on the surface of the activated carbon to make a mesh having a certain pore diameter on the surface, thereby allowing small molecules of free antigen or hapten to escape and being adsorbed, while the macromolecular complex is excluded. After the antigen and the antibody are reacted, the dextran-activated carbon is added and allowed to stand for 5 to 10 minutes, so that the free antigen is adsorbed on the activated carbon particles, and the particles are precipitated by centrifugation, and the supernatant contains the labeled antigen. 3. Determination of radioactivity: After separation of B and F, the radioactivity can be determined. There are two types of measuring instruments: a liquid scintillation counter (measuring beta rays) and a crystal scintillation counter (measuring gamma rays). The unit of counting is the number of electrical pulses output by the detector in units of cpm (number of pulses/min). A standard curve is required for each measurement, and the different concentrations of the standard antigen are plotted on the abscissa, and the corresponding radioactivity measured is plotted on the ordinate. The radioactivity may be optionally B or F, and the calculated values ​​B/B+F, B/F or B/B0 may also be used. Specimens should be determined in duplicate, the average value is taken, and the corresponding antigen concentration is detected on the standard curve. Not suitable for the crowd 1. Patients who have taken contraceptives, thyroid hormones, steroid hormones, etc., may affect the results of the examination and prohibit patients who have recently taken the drug history. 2, special diseases: patients with hematopoietic function to reduce disease, such as leukemia, various anemia, myelodysplastic syndrome, etc., unless the examination is essential, try to draw less blood. Adverse reactions and risks 1, subcutaneous hemorrhage: due to pressing time less than 5 minutes or blood draw technology is not enough, etc. can cause subcutaneous bleeding. 2, discomfort: the puncture site may appear pain, swelling, tenderness, subcutaneous ecchymosis visible to the naked eye. 3, dizzy or fainting: in the blood draw, due to emotional overstress, fear, reflex caused by vagus nerve excitement, blood pressure decreased, etc. caused by insufficient blood supply to the brain caused by fainting or dizziness. 4. Risk of infection: If you use an unclean needle, you may be at risk of infection.