Adrenals - Considerations
The adrenal glands are partially controlled by the brain.
The hypothalamus, a small area of the brain involved in hormonal regulation, produces corticotrophin-releasing hormone (CRH) and vasopressin (also known as antidiuretic hormone). Vasopressin and CRH induce the pituitary to secrete corticotrophin (also called adrenocorticotropic hormone or ACTH), which stimulates the adrenal glands to produce corticosteroids. The renin-angiotensin-aldosterone system, regulated mainly by the kidneys, causes the adrenal glands to produce a greater or lesser amount of aldosterone. The body controls the levels of corticosteroids according to your need. Levels tend to be much higher in the early morning than at the end of the day. When the body is stressed due to illness or another cause, the levels of corticosteroids increase dramatically.
Where are my adrenal glands?
We humans have two adrenal glands, each on top of a kidney. Each weighs around 4-5 g in an adult. The adrenals are detected for the first time in the 6th week of pregnancy.
What do my adrenal glands do?
The adrenal glands release different hormones that act as "chemical messengers". These hormones travel in the bloodstream and act on various tissues in the body to allow them to function properly. All adrenocortical hormones are steroidal compounds made from cholesterol.
What hormones do my adrenals produce?
The adrenal cortex produces three hormones:
Mineralocorticoids: the most important is aldosterone. This hormone helps to maintain the body's salt and water levels, which in turn regulate blood pressure. Without aldosterone, the kidney loses huge amounts of sodium and water, causing the person to become severely dehydrated and their blood pressure to drop.
Glucocorticoids: the most important is cortisol. It is involved in responding to disease and helps regulate the body's metabolism. Cortisol stimulates the body to produce glucose, helping the body to release the necessary storage ingredients (fat and muscle) for such production. Cortisol also has anti-inflammatory effects.
Adrenal androgens: male sex hormones, mainly dehydroepiandrosterone (DHEA) and testosterone. They all have weak effects, but participate in the early development of male sexual organs in childhood and female body hair during puberty. Adrenocorticotropic hormone (ACTH), secreted by the anterior pituitary gland, mainly affects the secretion of glucocorticoids and adrenal androgens by the adrenal gland and, to a much lesser extent, stimulates the release of aldosterone.
The adrenal medulla produces catecholamines. Catecholamines include adrenaline, norepinephrine and small amounts of dopamine - these hormones are responsible for all the physiological characteristics of the stress response.
Additional Information
When the adrenal glands become underactive, they tend to produce insufficient amounts of all adrenal hormones. In this way, many adrenal diseases affect the balance of water, sodium and potassium in the body, as well as the body's ability to control blood pressure and react to stress. An aldosterone deficiency causes the body to excrete large amounts of sodium and retain potassium, which results in low sodium levels and high potassium levels in the blood. Severe dehydration and a low sodium concentration reduce the volume of blood and can give rise to shock.
Corticosteroid deficiency causes extreme sensitivity to insulin, so the blood glucose level can drop so sharply that it is dangerous (hypoglycemia). This deficiency prevents the body from producing carbohydrates, which are necessary for cellular function, from proteins, in addition to preventing it from fighting infections properly and controlling inflammation. Muscles weaken and even the heart can weaken and become unable to pump blood properly. In addition, blood pressure can become dangerously low.
People with Addison's disease are unable to produce additional corticosteroids when they are stressed, so they are susceptible to severe symptoms and complications when facing illness, extreme tiredness, serious injury, surgery, or possibly severe psychological stress.
In Addison's disease, the pituitary gland produces more corticotrophin in an attempt to stimulate the adrenal glands. Corticotrophin also stimulates the production of melanin, so that the skin and mouth often have dark spots.