Adrenal glands, which are also called suprarenal glands, are small, triangular glands located on top of each kidney. An adrenal gland is made of 2 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 to secrete hormones that affect metabolism, blood chemistry, and some physical characteristics. Adrenal glands also secrete hormones that help a person cope with both physical and emotional stress.
Hormones secreted by the adrenal glands include:
Corticosteroid hormones (hydrocortisone or cortisol). Help control the body's metabolism of fats, proteins, and carbohydrates, suppress inflammatory reactions in the body, and affect the immune system function.
Aldosterone. Maintains blood volume and blood pressure by inhibiting the amount of sodium excreted into the urine.
Androgenic steroids (androgen hormones). Affect the development of pubic and underarm (axillary) hair, and production of adult body odor.
Hormones secreted by the adrenal glands also include:
Epinephrine (adrenaline). Increases the heart rate and force of heart contractions, facilitates blood flow to the muscles and brain, relaxes smooth muscles in arteries, converts starch to simple sugar in the liver, and other activities.
Norepinephrine (noradrenaline). Increases blood pressure through strong vasoconstrictive effects (narrowing of the blood vessels), but exerts little effect on smooth muscles, metabolic processes, and cardiac output.
Certain adrenal gland disorders are characterized by an inability of the adrenal glands to produce cortisol (also known as hydrocortisone) and aldosterone, often due to certain missing enzymes (substances that speed up or cause chemical reactions). With the most common defects in adrenal synthetic pathways, intermediate chemicals may be diverted within the adrenal gland to produce excessive androgens, which can lead to masculinization of affected females.