Adrenal Glands

Anatomy of the adrenal glands:

Adrenal glands, which are also called suprarenal glands, are small, triangular glands located on top of both kidneys. An adrenal gland is made of two parts: the outer region is called the adrenal cortex and the inner region is called the adrenal medulla.

Function of the adrenal glands:

The adrenal glands work interactively with the hypothalamus and pituitary gland in the following process:

• the hypothalamus produces corticotropin-releasing hormones, which stimulate the pituitary gland.
• the pituitary gland, in turn, produces corticotropin hormones, which stimulate the adrenal glands to produce corticosteroid hormones.

Both parts of the adrenal glands -- the adrenal cortex and the adrenal medulla -- perform very separate functions.

What is the adrenal cortex?

The adrenal cortex, the outer portion of the adrenal gland, secretes hormones that have an effect on the body's metabolism, on chemicals in the blood, and on certain body characteristics. The adrenal cortex secretes corticosteroids and other hormones directly into the bloodstream. The hormones produced by the adrenal cortex include:

• corticosteroid hormones
  • hydrocortisone hormone - this hormone, also known as cortisol, controls the body's use of fats, proteins, and carbohydrates.
  • corticosterone - this hormone, together with hydrocortisone hormones, suppresses inflammatory reactions in the body and also affects the immune system.
• aldosterone hormone - this hormone inhibits the level of sodium excreted into the urine, maintaining blood volume and blood pressure.
• androgenic steroids (androgen hormones) - these hormones have minimal effect on the development of male characteristics.

What is the adrenal medulla?

The adrenal medulla, the inner part of the adrenal gland, is not essential to life, but helps a person in coping with physical and emotional stress. The adrenal medulla secretes the following hormones:

• epinephrine (also called adrenaline) - this hormone increases the heart rate and force of heart contractions, facilitates blood flow to the muscles and brain, causes relaxation of smooth muscles, helps with conversion of glycogen to glucose in the liver, and other activities.
• norepinephrine (also called noradrenaline) - this hormone has little effect on smooth muscle, metabolic processes, and cardiac output, but has strong vasoconstrictive effects, thus increasing blood pressure.

From: University of Maryland Center for Diabetes and Endocrinology

Overactive adrenal glands (Cushing's syndrome)

Overview

If your child’s adrenal glands produce excessive amounts of certain hormones, they are said to be overactive. The symptoms (and treatment) of overactive adrenal glands depends on which hormone is being overproduced.
Some of the most commonly overproduced hormones are:

• Androgenic steroids (also known as androgen hormones)
  • Testosterone is one of the most well-known androgen hormones. Excessive production of this or other androgen hormones can lead to exaggerated male characteristics in both men and women (like excess hair on the face and body, baldness, acne, a deeper voice and increased muscle mass).
  • If a female fetus is exposed to high levels of androgens early during a mother’s pregnancy, her genitals may develop abnormally. Young boys who experience high levels of androgen levels may grow faster, but their bones may also mature faster and stop growing too soon.
• Aldosterone hormone
  • Overproduction of aldosterone hormone can lead to high blood pressure and to symptoms associated with low levels of potassium (like weakness, muscle aches, spasms and sometimes paralysis).
• Corticosteroids
  • An overproduction of corticosteroids leads to the condition known as Cushing’s syndrome. Rare in children, it’s more commonly seen in adults.
  
  

What causes Cushing’s syndrome?
Cushing’s syndrome—the overproduction of corticosteroids—may be caused by an overproduction of cortisol (the hormone that controls the adrenal gland) by the pituitary gland. Other causes of Cushing’s syndrome include:

• certain lung cancers and other tumors outside the pituitary gland
• benign (non-cancerous) or cancerous tumors on the adrenal gland(s)

What are the symptoms of Cushing’s syndrome?
Children and adolescents with Cushing's syndrome experience weight gain, growth retardation and hypertension (high blood pressure). Other symptoms may include:

• upper body obesity
• round or moon-shaped face
• increased fat around neck
• thinning arms and legs
• fragile and thin skin
• darkened pigmentation of the skin
• acne
• bruising
• stretch marks on abdomen, thighs, buttocks, arms, and breasts
• bone and muscle weakness
• severe fatigue
• high blood sugar
• irritability and anxiety
• excessive hair growth in females
• irregular or stopped menstrual cycles in females
• reduced sex drive and fertility in males

How do doctors diagnose an overactive adrenal glands?
In addition to a complete medical history and physical examination, your child’s doctor will order specific blood and/or urine tests to measure hormone levels.

How can doctors tell if my child has Cushing’s syndrome?
In addition to a complete medical history and physical examination, your child’s doctor may request some or all of the following procedures:

• x-ray - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones and organs onto film
• 24-hour urinary test (urine is collected over a 24-hour period to measure corticosteroid hormones)
• computerized tomography scan (Also called a CT or CAT scan) - a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body
• magnetic resonance imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radiofrequencies and a computer to produce detailed images of organs and structures within the body
• dexamethasone suppression test (to differentiate whether the excess production of corticotropins originates from the pituitary gland or tumors elsewhere)
• corticotropin-releasing hormone (CRH) stimulation test (to differentiate whether the cause is a pituitary tumor or an adrenal tumor)

How are overactive adrenal glands/Cushing’s syndrome treated?
Treatment for overactive adrenal glands may include surgical removal of growths on the adrenal gland(s) or the adrenal gland(s) itself. Your doctor may also prescribe medications that block the excessive production of certain hormones.

From https://web1.tch.harvard.edu/az/Site1405/mainpageS1405P0.html