Abstract. Cortisol is a hormone that is produced in the adrenal cortex. It protects the body from stress, regulates blood pressure, and is involved in the metabolism of proteins, fats and carbohydrates. The release of cortisol is regulated by adrenocorticotropic hormone (ACTH), produced in the pituitary gland, a small gland located on the lower part of the brain. The concentrations of ACTH and cortisol in the blood are regulated by feedback. A decrease in cortisol concentration increases the production of ACTH, resulting in stimulation of the production of this hormone until it returns to normal. An increase in the concentration of cortisol in the blood, on the contrary, leads to a decrease in the production of ACTH