The digestive system builds the dietary carbohydrates that are contained in, for example, sugar, bread and other cereal products, to glucose (dextrose) from. This is absorbed by the intestinal wall into the blood and distributed throughout the body.
The pancreas produces in ?-cells of the islets of Langerhans of the insulin hormone. Insulin increases in muscle and fat cells, the permeability of cell membranes to glucose. In the cells the glucose is consumed for energy. Insulin also causes the glucose uptake in the liver cells, which they store in the form of glycogen. The blood sugar rises in the digestion phase and will then (a half to two hours after the last feeding) held constant within narrow limits, 80-120 mg / dl or 4,5-6,7 mmol / l. Even in long fasting blood glucose levels remain at normal levels. This is essentially the liver: first, the stored glycogen is broken down and re-released into the blood, on the other hand constantly glucose from smaller building blocks formed new (gluconeogenesis).
If the insulin-producing ?-cells do not work properly or because of pathological processes are no longer there, missing both the uptake of blood sugar derailed in the tissue and the inhibition of sugar formation in the liver and the process. The liver can, under these conditions every day up to 500 grams of glucose to produce new. This is also a rise in blood sugar levels in diabetics explained without food.
In addition, insulin has a third effect. Indeed, it is the only hormone in the human body, which builds body and ensures that the fat remains in the depots. A major feature of insulin deficiency is therefore an extreme weight loss.
In diabetes mellitus (insulin deficiency or reduced insulin action), so glucose can not be added to the cells, but the glucose remains in the blood and glucose formation in the liver proceeds unabated, neither of which leads to an increase in blood sugar.
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