What raises blood glucose level and causes insulin response?
QUESTION: What raises blood glucose level and causes insulin response?
ANSWER: Hi there,
It is true that glucose metabolism is very complex as it is regulated by several hormones. Some of them are leading to the blood glucose elevation and only one hormone, secreted from the pancreas, is causing reduction of the blood glucose concentration (i.e. insulin).
When it's secretion is reduced, you might be suffering from hyperglycemia, and eventually diabetes.
You have to know that there is a central nerve in the brain, which is regulating the blood glucose level. The major goal of this center is to keep the blood glucose level within the normal range -3.5.-6.1mmol/l.
How does this nerve center work?
This nerve center works by stimulating the secretion of insulin when the amount of glucose is high. Meanwhile it stimulates the secretion of the other hormones when the blood glucose concentration is low.
Furthermore, the insulin secretion is stimulated even by the stretch receptors situated in the stomach. When the stomach is stretched, after having a meal, this will stimulate these receptors, leading to insulin secretion.
In this way, your organism is keeping the blood glucose concentration within the normal values without waiting for it to rise up.
As it was mentioned, there are several other hormones which are increasing the blood glucose concentration, and they are: cortisol, adrenalin, glucagon, noradrenalin, T3 and T4.
These hormones are secreted from different glands, but the common between them is their action to increase blood glucose.
You have to know that cortisol secretion for example, is having peaks and drops during the day, including the morning peak, just after waking up, and in 3-4 o’clock in the afternoon. These peaks are associated with an elevation in blood glucose level.
Now, coming to insulin. As I have mentioned above, the insulin is reducing the blood glucose concentration, but if there is no other hormone which able to counteract the effect of insulin, you are going to fall into hypoglycemia.
For not allowing this, the nerve center, responsible for the blood glucose concentration, is increasing the secretion of glucagon, about 20-30 minutes after having a meal, if you are having normal glucose metabolism.
The blood glucose elevation caused by adrenalin and noradrenalin is observed when you are under stress. As you probably know, these two hormones are known as stress hormones, and they are increasing the blood glucose level in purpose to ensure the body enough energy (glucose) to handle with the stress.
Important fact about T3 and T4 (thyroid hormones) is that they are regulating the blood glucose concentration, because they are defining the speed of the metabolic process in the organism.
When their secretion is elevated, the speed of the metabolic processes is increased. This is leading to the usage of large amount of glucose and respectively reduction of the blood glucose concentration.
This might happen during the day; while during night, the secretion of these hormones is reduced, which is characterized by low speed of the metabolic process.
Because of the low speed, the organism is not able to use the blood glucose at once, which is causing blood glucose elevation. Consequently, the pancreas will be stimulated to secrete more insulin in case you have a normal glucose metabolism.