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Disorders affecting the adrenal gland
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, called the adrenal cortex, and the inner region, called the adrenal medulla. The adrenal glands work interactively with the hypothalamus and pituitary gland, as well as secrete hormones that affect metabolism, blood chemicals, and certain body characteristics. Adrenal glands also secrete hormones that help a person cope with both physical and emotional stress.
Hormones secreted by the adrenal glands include the following:
- Adrenal cortex
- Corticosteroid hormones (hydrocortisone or cortisol) - to help control the body's use of fats, proteins, and carbohydrates, suppress inflammatory reactions in the body, and affect the immune system function.
- Aldosterone - inhibits the level of sodium excreted into the urine, and maintains blood potassium levels, blood volume and blood pressure.
- Androgenic steroids (androgen hormones) - hormones that have an effect on the development of some types of hair growth, acne, and male characteristics.
- Adrenal medulla
- Epinephrine (adrenaline) - 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 (noradrenaline) - this hormone has little effect on smooth muscle, metabolic processes, and cardiac output, but has strong vasoconstrictive effects (narrowing of the blood vessels), thus, increasing blood pressure.
If the adrenal glands cannot produce enough cortisol the hypothalamus detects the low blood levels of cortisol. The hypothalamus, in turn, stimulates the pituitary gland to make ACTH in order to stimulate the adrenal glands.
In some cases, the ACTH stimulation causes the glands to grow. If there is a defect in the production of cortisol due to deficiency of an enzyme (usually 21-hydroxylase), overstimulation of the adrenal glands can also lead to overproduction of androgens, which can lead to masculinization. This situation occurs in patients with a condition called congenital adrenal hyperplasia or CAH. Some patients with CAH are unable to make aldosterone. Treatment includes replacement of cortisol with cortisosteroid medication. This reduces the ACTH-stimulation of the gland and in turn, the androgen production is reduced. Some patients also require treatment with fludrocortisone if they cannot make aldosterone.
Disorders of the adrenal glands require clinical care by a physician or other healthcare professional. Listed in the directory below are some of these disorders: