Antagonist glucagon
Unlike insulin, which lowers blood sugar levels, the hormone glucagon increases the amount of sugar in the blood. It is the direct counterpart to insulin. So glucagon is a catabolic hormone that breaks down and releases sugar from energy stores such as the liver.
It also activates some enzymes that help break down fat. Glucagon is also produced in the pancreas, released into the blood and then bound to cells by receptors. Through the binding, the energy stores within the cells, especially in fat and liver cells, are broken down.
So if we have not eaten for some time, for example at night, and have not directly supplied our body with sufficient energy, glucagon is released. Enzymes of the sugar metabolism, which are stimulated by insulin, are inhibited by glucagon and vice versa. They therefore create a balance that is very finely tuned. It protects us from having too little or too much sugar in our blood and is a good example of the balance that must be constantly maintained in order for our body to function fully.
Influence on the sugar level in the blood
Sugar is a main supplier of energy in the human body. Therefore, the metabolism ensures that a certain amount of it is always freely available in the blood so that it is quickly available when it is needed. If this were not the case, every time cells need sugar, a storage tank would first have to be broken down, the sugar would have to be absorbed into the blood and then back into the cells that need it.
This simply takes too long. When fasting, the sugar concentration, i.e. the blood sugar level, should be less than 100 mg per deciliter, i.e. less than 1000 mg per liter.
After a meal, however, this value increases many times over. In order to get the free sugar out of the blood, insulin is needed, which, as described above, lowers the blood sugar level again by allowing the cells to absorb sugar. Therefore, in stressful situations such as class tests or sports, it can help to eat pure sugar in the form of glucose. It does not have to be broken down in the intestine, but can be absorbed very quickly into the blood and thus increase the amount of sugar that is freely available for direct consumption.
What happens if I become insulin resistant?
If insulin no longer has any effect on cells and is therefore no longer able to lower the blood sugar level, this is called insulin resistance. It can have various causes, which are still largely unknown. Since insulin resistance is the basis for diabetes mellitus type 2, intensive research is being conducted in this area.
It is certain that type 2 diabetes is associated with severe overweight and is certainly also genetically predisposed. It is suspected that either the receptors no longer react correctly to the binding of insulin or that they are no longer produced in sufficient numbers. It is also possible that the body forms antibodies against insulin, which catch it in the blood before it can bind to cells and act.
However, the consequence is always the same: Insulin is missing from the cells as a signalling substance to build in receptors for sugar. As a result, the cells lack the important energy substance and the sugar concentration in the blood rises dangerously. The excess sugar then binds to substances such as proteins and fats found in the blood.
They accumulate in the blood, attach themselves to vessel walls and prevent a smooth blood flow. This leads to vascular damage and, in the long term, to damage throughout the body, including kidney and eye diseases, as well as damage to nerve cells. You can find an overview of all topics in internal medicine under Internal Medicine A-Z. – Insulin
- Insulinoma
- Diabetes mellitus
- Metformin
- Blood sugar
- Blood glucose monitoring
- Lantus®
- Glucophage
- Insuman comb
