ACTH (Adrenocorticotropic Hormone, Corticotropin, Adrenocorticotropic Hormone, ACTH)

Brief description of the substance being determined Adrenocorticotropic hormone ACTH is a peptide hormone (consists of 39 amino acids) produced by the anterior pituitary gland. ACTH secretion is under the stimulating control of corticotropin-releasing hormone of the hypothalamus. ACTH, in turn, stimulates the production of cortisol by the adrenal cortex. The activity of the hypothalamic-pituitary-adrenal system is influenced by an internal circadian rhythm (at 6-8 o'clock the concentration of ACTH is maximum, at 21-22 o'clock - minimum). With a sharp change in time zones, the circadian rhythm of ACTH secretion normalizes within 7-10 days. The hypothalamic-pituitary-adrenal system, under the influence of the central nervous system and humoral factors, is activated in states of stress (both physical and emotional). A severe stressful situation leads to disruption of the circadian rhythm, a sharp increase in cortisol in the blood 25-30 minutes after the onset of stress. Infections, inflammatory processes accompanied by the release of cytokines also cause activation of the hypothalamic-pituitary-adrenal system. Cortisol, the end product of the system, acts on various organs and tissues, activating numerous adaptive reactions. An increase in the concentration of cortisol by feedback mechanisms inhibits the secretion of both hypothalamic corticotropin-releasing hormone and ACTH. The half-life of ACTH in the blood is short, measured in minutes. In primary adrenal insufficiency, the ACTH level is elevated, and the cortisol level is reduced; in secondary adrenal insufficiency (pituitary), the ACTH level is reduced or at the lower limit of normal, the concentration of cortisol is reduced. For what purpose is the level of Adrenocorticotropic hormone determined in the blood serum Since ACTH is the most important regulator of the synthesis and secretion of hormones of the adrenal cortex, determining its level in the blood is used to identify dysfunction of the adrenal cortex and related pathologies. What can affect the level of Adrenocorticotropic hormone in the blood It should be taken into account that the ACTH content is affected by the phase of the menstrual cycle, pregnancy, emotional state, pain, increased body temperature, physical activity, surgical interventions.