This glossary contains short definitions for the medical terms used throughout this site.

ACE inhibitor

Angiotensin-converting-enzyme inhibitors (ACE inhibitors) are a class of medications used primarily for the treatment of high blood pressure and heart failure. They work by causing relaxation of blood vessels as well as a decrease in blood volume, which leads to lower blood pressure and decreased oxygen demand from the heart. They inhibit the angiotensin-converting enzyme, an important component of the renin–angiotensin system.


Adrenocorticotropic hormone (ACTH) is a hormone produced in the anterior, or front, pituitary gland in the brain. The function of ACTH is to regulate levels of the steroid hormone cortisol, which is released from the adrenal gland. ACTH is also known as: adrenocorticotropic hormone.


Adenomas are benign tumors starting in the epithelial tissue of a gland or gland-like structure. The epithelial tissue is the thin layer of tissue covering organs, glands, and other structures. Adenomas might also grow in the liver or the adrenal, pituitary, or thyroid gland. An Aldosterone-Producing Adenoma (APA) is one of the subtypes of primary aldosteronism.

Adrenal gland

The adrenal glands are small glands located on top of each kidney. They produce hormones that you can’t live without, including aldosterone, cortisol, and sex hormones.

Adrenal Venous Sampling (AVS)

Adrenal venous sampling (AVS) is a procedure entailing the measurement of aldosterone from both adrenal veins to diagnose an adrenal source of excess aldosterone secretion. Because unilateral forms of primary aldosteronism may be treated surgically, identifying these sources by AVS is critical.


An adrenalectomy is a surgical procedure performed to remove tumors of the adrenal glands including: benign tumors (such as an aldosterone-producing adenoma) and cysts, and malignant primary tumors.

Adrenocortical carcinoma

Adrenocortical carcinoma is a rare disease in which malignant (cancer) cells form in the outer layer of the adrenal gland.


Aldosterone, the main mineralocorticoid hormone, is a steroid hormone produced by the zona glomerulosa of the adrenal cortex in the adrenal gland. It is essential for sodium conservation in the kidney, salivary glands, sweat glands and colon.

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