Defective insulin secretion

Insulin is one of the important hormones in the body. If symptoms of insulin secretion deficiency occur, we should supplement insulin in time, otherwise hypoglycemia will occur. Because insulin is the main hormone that controls blood sugar, it is secreted by pancreatic cells. Generally, the secretion of insulin will increase after meals. In cases of insulin secretion deficiency, we should check the secretion of pancreatic islet cells.

Insulin is secreted by the B cells of the pancreatic islets of the human pancreas. Congenital or acquired dysfunction of the pancreatic islet B cells can lead to insufficient insulin secretion, thereby causing diabetes.

Diabetes is divided into type 1 and type 2. Type 1 diabetes is a condition in which pancreatic B cells cannot secrete insulin due to a congenital defect, so these patients need lifelong treatment with artificial insulin. Type 2 diabetes, which is what we usually call diabetes, when the disease progresses to a certain extent, the pancreatic B cells are damaged due to various reasons, and the ability to secrete insulin will decrease. At this time, exogenous insulin is needed to supplement the lack of secretion in the body and control blood sugar. On the other hand, it can also give the damaged pancreatic B cells a chance to repair themselves. Therefore, some patients will find that the amount of insulin required is getting less and less after using it for a period of time, and they may even stop using insulin and take medication alone. This is a manifestation of the recovery of their own pancreatic B cell function. Of course, the extent of recovery varies from individual to individual, and it is also related to the severity of the initial damage.

How to assess insulin secretion defects?

1. Blood sugar level is the simplest and most reliable indicator of insulin secretion and action. Any increase in blood sugar means insulin deficiency, which means impaired beta cell function. Therefore, blood sugar level is the most direct reflection of β-cell function, but not all people with the same blood sugar level have the same β-cell function. This is because blood sugar level is affected by both the insulin secretion capacity and the body's insulin sensitivity.

2. Plasma insulin level is another important indicator reflecting β-cell function, but sometimes there are problems. The reason is that insulin secretion is affected by the "double load" - sugar load and insulin resistance.

3. Determination of abnormal insulin secretion at the first time: Administer the maximum stimulatory dose of arginine (5g) intravenously, measure plasma insulin at 2, 4 and 6 minutes, and the rapid insulin secretion, that is, the difference between the mean insulin value from 2 to 6 minutes and the fasting insulin, is considered to be the β-cell function. A level less than 24.95 mu/l is considered to be a defect in insulin secretion. It is currently mainly used in scientific research.

In summary, the assessment of β-cell function is more difficult and has more interference factors than the assessment of insulin sensitivity, and there is no gold standard yet. The existing assessment methods each have their own advantages and disadvantages and are only suitable for assessing specific populations. When using them, we should play to their strengths and avoid their weaknesses. Clinical assessment should be "rough" rather than "detailed". Methods for evaluating insulin sensitivity and β-cell function are still being explored.