What is HPA axis activation?
The combined system of CRH-ACTH-cortisol release is referred to as the hypothalamic-pituitary-adrenal axis (or HPA axis). The ultimate result of the HPA axis activation is to increase levels of cortisol in the blood during times of stress.
The hypothalamic pituitary adrenal (HPA) axis is our central stress response system. The HPA axis is an eloquent and every-dynamic intertwining of the central nervous system and endocrine system. This system works in a fairly straight-forward manner.
- Cortisol is a steroid hormone, in the glucocorticoid class of hormones. When used as a medication, it is known as hydrocortisone. It is produced in humans by the zona fasciculata of the adrenal cortex within the adrenal gland. It is released in response to stress and low blood-glucose concentration.
- Adrenaline is delivered into your neurobiological system by what is known as the hypothalamic-pituitary-adrenal axis, or the HPA axis. The HPA axis is named after three components: the hypothalamus, the pituitary gland, and the adrenal glands.
- Adrenal glands: Two glands that sit on top of the kidneys that release the hormone cortisol. Hypothalamus: A part of the lower middle brain that tells the pituitary gland when to release hormones. Ovaries: The female reproductive organs that release eggs and produce sex hormones.
HPA Axis Dysfunction. The HPA axis is a complicated set of relationships and signals that exist between the hypothalamus, the pituitary gland and the adrenals. This relationship is an absolutely indispensable part of our existence.
- The adrenal glands are small glands located on top of each kidney. They produce hormones that you can't live without, including sex hormones and cortisol. Cortisol helps you respond to stress and has many other important functions. With adrenal gland disorders, your glands make too much or not enough hormones.
- Addison's disease symptoms usually develop slowly, often over several months, and may include:
- Extreme fatigue.
- Weight loss and decreased appetite.
- Darkening of your skin (hyperpigmentation)
- Low blood pressure, even fainting.
- Salt craving.
- Low blood sugar (hypoglycemia)
- Nausea, diarrhea or vomiting.
- Abdominal pain.
- Adrenal insufficiency can be primary or secondary. Addison's disease, the common term for primary adrenal insufficiency, occurs when the adrenal glands are damaged and cannot produce enough of the adrenal hormone cortisol. The adrenal hormone aldosterone may also be lacking.
Adrenal insufficiency is a condition in which the adrenal glands do not produce adequate amounts of steroid hormones, primarily cortisol; but may also include impaired production of aldosterone (a mineralocorticoid), which regulates sodium conservation, potassium secretion, and water retention.
- Cortisol receptor sites and cortisol secretion from the adrenal cortex increase. Anabolic steroid use decreases testosterone secretion. People who stop taking steroids are also hampered with less male hormone than usual during the "off" periods. (3) Cortisol suppresses the immune system.
- The most common symptoms are severe fatigue, loss of appetite, weight loss, nausea, vomiting, diarrhea, muscle weakness, irritability, and depression. Since aldosterone is usually present, low blood pressure and muscle spasms are not as likely as they are in primary adrenal insufficiency.
- Glucocorticoids are a class of corticosteroids, which are a class of steroid hormones. The name glucocorticoid (glucose + cortex + steroid) is composed from its role in regulation of glucose metabolism, synthesis in the adrenal cortex, and its steroidal structure (see structure to the right).
Updated: 14th October 2018