Proinsulin

Proinsulin is a precursor of insulin, composed of insulin and C peptide, and has dual immunological activity, which can bind to both insulin antibodies and C-peptide antibodies. Proinsulin is synthesized and secreted by islet beta cells, mainly in the kidney catabolism. Under physiological conditions, only a very small amount of proinsulin is released into the blood. Under pathological conditions, islet β cells release more proinsulin and blood levels of proinsulin increase. Basic Information Specialist classification: growth and development examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Tips: Other solutions can be stored at -20 °C. Normal value Radioimmunoassay: <0.2 μg/L. Clinical significance (1) Plasma proinsulin levels are significantly elevated in diabetic patients. Type 1 diabetes due to the extremely decreased insulin synthesis and secretion of islets, the newly synthesized proinsulin is released into the blood without conversion to insulin, resulting in elevated plasma proinsulin. Studies have shown that some patients with type 2 diabetes who present with hyperinsulinemia are actually hyperinsulinemia because of islet β-cell dysfunction and increased secretion of proinsulin. (2) Plasma proinsulin levels were significantly elevated in patients with islet β-cell tumor and familial hyperinsulinemia. (3) When chronic renal insufficiency, the catabolism of proinsulin is reduced, which can lead to an increase in plasma proinsulin; elevated levels of plasma proinsulin may also occur in hyperthyroidism. Low results may be diseases: diabetes, elderly hypoglycemia results may be high disease may be: elderly hypoglycemia coma, insulinoma precautions (1) The amount must be accurate during the operation. (2) Potassium iodide, chloramine T and sodium metabisulfite solution were prepared a few minutes before use. Other solutions can be stored at -20 °C. (3) After adding dextran activated carbon, let stand at 4 ° C for 15 min, do not extend the time or increase the temperature, otherwise it will lead to an increase in the sediment count. (4) If there is an insulin release kit sold in the market, the steps of preparation of anti-insulin antiserum, insulin labeling, etc. may be omitted, and the operation method shall be carried out in strict accordance with the instructions attached to the kit. Inspection process Subjects were venously collected and assayed in time for serum separation. Add the immunological reagent and mix well. Allow to stand at 4 ° C for 20 min, centrifuge 2000 g, 20 min, discard the supernatant, and measure the radioactivity. 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.