Cortisol is a steroid hormone of the bundle zone of the adrenal cortex, which performs a number of important functions:
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Stimulation of glyconeogenesis: the formation of glucose in the liver, as an energy source for the body, from other various substances.
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Prevention of an inflammatory reaction: suppresses the interleukin-2 receptor on T-helpers. T-helpers become unable to stimulate B-lymphocytes, which stop releasing antibodies (immunoglobulins).
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Antiallergic effect: reduction of histamine production and stabilization of lysosomal membranes.
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Stimulation of liver detoxification function: by induction of tryptophanoxygenase.
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Stimulation of glycogenolysis: the rapid breakdown of glycogen to glucose. This function is very important in a stressful situation when the body needs a lot of energy.
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Increases the production of amino acids: by reducing collagen synthesis (which, at high concentrations of cortisol, leads to a loss of skin elasticity).
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Slows down the growth of the protein component of the bone and removes calcium from it – which is manifested by osteoporosis.
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Insulin resistance.
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Stimulation of hydrochloric acid secretion by the stomach.
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Slightly slows down the excretion of sodium from the body through the intestines.
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Increases blood pressure by increasing the sensitivity of blood vessels to adrenaline. The level of the hormone in the blood is regulated by the principle of feedback. Initially, the pituitary gland prompts the adrenal glands to produce the hormone, if the concentration of cortisol decreases, then a signal about this enters the hypothalamus, the hypothalamus, in turn, secretes substances that affect the pituitary gland. Next, the pituitary gland produces ACTH, which goes to the adrenal glands to stimulate the production of their hormones. As soon as hormone levels return to normal, the system shuts down.
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The concentration of cortisol in the blood is characterized by fluctuations during the day: in the morning hours (7-10 a.m), the amount of hormone is maximum, then there is a decrease in the substance – the minimum is noted at 4.00--8.00 p.m. During pregnancy, cortisol levels increase 2-5 times.