The adrenal glands are a set of paired organs located on top of the kidneys. Their function, however, is unrelated to that of the kidneys. Rather than providing filtration and excretion like the kidneys do, the adrenal glands are hormone producing glands. The adrenal gland can be divided into two sections, the medulla and the cortex. The medulla produces hormones called catecholamines whereas the cortex produces hormones that regulate salt, sugar and sexual development.
Catecholamine Production
Catecholamines are a group of neurologic hormones commonly referred to as adrenaline. Epinephrine, norepinephrine and dopamine make up this group. These hormones are also produced by the nervous system. They serve as transmitters of neurologic impulses throughout the body. One disease that affects the adrenal medulla is pheochromocytoma. This is a rare tumor that causes the medulla to produce catecholamines in excess. High blood pressure, headaches, chest palpitations and sweating are commonly seen with pheochromocytoma. The treatment is surgical removal of the affected gland.
Salt-regulating Hormone
The adrenal cortex produces hormones that regulate salt balance. The most important of these is called aldosterone. Aldosterone regulates salt by increasing the absorption of salt in the kidneys. Excess aldosterone is called hyperaldosteronism. Patients present with high blood pressure in these cases. Causes for hyperaldosteronism range from heart failure to cirrhosis. In some cases, a single non-malignant adrenal growth, called an adrenal adenoma, will produce excess aldosterone. Surgical removal of the adrenal gland containing the adenoma can successfully treat this disease.
Sugar-regulating Hormone
The primary sugar regulating hormone produced in the adrenal cortex is cortisol. While cortisol has other functions, its main action is to increase blood sugar levels. When a patient is stressed emotionally or physically, cortisol rises in response. Patients with excessive cortisol levels have Cushing's syndrome. This syndrome is manifests as a myriad of symptoms including weight gain, diabetes, fatigue and high blood pressure. The syndrome can be the result of stimulation of the adrenal by another endocrine organ or by tumors or the result of an adrenal adenoma that produces cortisol excessively. Treatment is directed at the particular organ causing the stimulation.
Sex Developmental Hormones
The adrenal cortex produces several sex hormones called androgens. While they have several effects, the major one is to convert testosterone precursors into testosterone proper. Adrenal androgens play a major role in development of fetal male genitals and also in development of secondary male sexual characteristics at puberty. Excess androgens in boys leads to accelerated puberty and in girls, the development of masculine characteristics like voice deepening and excess facial hair. Rarely, excess androgen will result in increasing feminine characteristics. Treatment includes surgery and possibly medication.
Adrenal Incidentalomas
Adrenal incidentalomas are lesions discovered accidently on CT scans that have been ordered for other reasons. The conundrum is how to care for them. After establishing that the lesion is not cancerous and not producing excess hormones, the goal is to determine which lesions need to be removed and which can be left alone. Generally, size and age are important factors in this decision.
