Definition
ACTH is the abbreviation for Adrenocorticotropic Hormone. This hormone is produced in the pituitary gland and released into the blood. By releasing ACTH, the production and release of cortisone in the adrenal cortex is controlled.
Insulin secretion is also influenced by ACTH. During the course of the day, the ACTH level in the blood changes. This is called circadian rhythm. Various environmental influences, such as temperature, can influence production. In various diseases, the ACTH level in the blood can be changed and this has serious consequences for the whole body.
The function of ACTH
The adrenocorticotropic hormone from the adenohypophysis belongs to the hypothalamic-pituitary-adrenal axis. The hypothalamus is an important area in the brain that controls numerous body functions. The pituitary gland is a hormonal gland that controls the hormonal balance.
First, a hormone is secreted in the hypothalamus, which triggers the release of ACTH in the pituitary gland, which then reaches the adrenal cortex and stimulates the release of the hormone cortisol. Cortisol has many effects in the body. In the liver, cortisol leads to the production of sugars, gluconeogenesis, and the storage of this sugar as an energy reserve.
In the arms and legs, cortisol leads to a reduction in fat, as this fat is used to provide energy. Cortisol also raises blood pressure. Muscle tissue is more likely to be broken down and the bones are also broken down.
Cortisol also has an immunosuppressive effect. This means that the production of ACTH leads via cortisol to a weakening of the body’s own defences. Too much cortisol leads to feedback and the body produces less ACTH and consequently less cortisol is released.
Hormones, such as cortisol, can also be used as drugs to specifically control other hormone levels, such as ACTH. . Different hormones can influence each other and inhibit or stimulate production.
These systems are closely coordinated. ACTH is a component of the hypothalamic-pituitary-adrenal axis. The hypothalamus (the brain‘s superior control centre) produces CRH, which reaches the pituitary gland.
There, ACTH is subsequently produced and released into the blood. When ACTH reaches the adrenal cortex, cortisol is released. However, if ACTH reaches the hypothalamus again in too large quantities, the production of CRH and all subsequent hormones is inhibited.
Cortisol can also influence the other steps. If the cortisol level is too high, less CRH and less ACTH will be produced. However, the release of the individual steps also depends on external factors.
First, production follows a circadian rhythm. This means that different amounts of hormones are released depending on the time of day, in a 24-hour rhythm. Temperature or physical or psychological stress can also regulate hormone release. This is why people who are permanently under stress have higher cortisol levels and a weaker body’s own defence system.
