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:
Corticosteroid hormones (hydrocortisone or cortisol). Hormones that 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 volume and blood pressure.
Androgenic steroids (androgen hormones). Hormones that have an effect on the development of male characteristics.
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, 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.
Certain adrenal gland disorders are characterized by an inability of the adrenal glands to produce cortisol (also known as hydrocortisone hormone) and aldosterone, often due to certain missing enzymes (proteins that speed up or cause chemical reactions). The result is enlarged adrenal glands due to overstimulation from the hypothalamus which detects the low levels of hormones. The hypothalamus, in turn, stimulates the pituitary gland to stimulate the adrenal glands. Overstimulation of the adrenal glands can lead to overproduction of androgens, which can lead to masculinization.