Adrenal Gland refers to a pair of small endocrine glands located on top of each kidney that produce several essential hormones, including cortisol, aldosterone, and adrenal androgens. These glands are also called the suprarenal glands, reflecting their anatomic position. The adrenal glands are part of the endocrine system and help regulate stress responses, blood pressure, fluid balance, and aspects of metabolism. Their function depends on two major regions with distinct embryologic origins and hormone outputs: the adrenal cortex and the adrenal medulla. Hormone production can be influenced by pituitary signaling, autonomic nervous system input, and circulating factors such as angiotensin II and adrenocorticotropic hormone (ACTH). Disruption of adrenal gland structure or hormone secretion can contribute to a range of endocrine disorders, including conditions affecting cortisol or aldosterone levels.

Adrenal gland disorders may present with symptoms related to excess or deficiency of specific hormones. Cortisol-related problems can manifest as changes in energy, weight, glucose regulation, skin findings, and susceptibility to infection, depending on whether cortisol levels are too high or too low. Aldosterone-related problems commonly involve blood pressure changes, electrolyte abnormalities such as low potassium (hypokalemia) or sodium retention, and symptoms related to volume status. Adrenal medulla involvement is classically associated with catecholamine excess, which can produce episodic headaches, palpitations, sweating, and blood pressure surges. Presentations can vary by age, comorbidities, and the underlying cause, including autoimmune, genetic, infiltrative, or tumor-related mechanisms. Some conditions are subtle and discovered incidentally through imaging or laboratory testing, while others progress more rapidly.

Historically, the adrenal glands were recognized anatomically long before their endocrine roles were fully understood. The concept that these glands produce hormones emerged as experimental physiology clarified that adrenal tissue influences systemic function beyond local anatomy. Over time, medical classification separated adrenal disorders by the hormone pathway involved, leading to distinct categories such as cortisol disorders, mineralocorticoid disorders, and catecholamine-related conditions. Epidemiologically, many adrenal disorders are uncommon, but adrenal incidentalomas—unexpected adrenal masses found during imaging for other reasons—are increasingly detected due to widespread use of computed tomography (CT) and magnetic resonance imaging (MRI). This shift has changed clinical focus toward distinguishing benign from clinically significant lesions and characterizing hormone activity. Advances in immunohistochemistry, molecular genetics, and endocrinologic testing have refined how adrenal conditions are categorized and understood.

The adrenal cortex is organized into zones that produce different steroid hormones: the zona glomerulosa primarily synthesizes aldosterone, the zona fasciculata produces cortisol, and the zona reticularis generates adrenal androgens. The adrenal medulla produces catecholamines such as epinephrine and norepinephrine, which are regulated by sympathetic nervous system activity. Many adrenal conditions are classified by whether they involve hormone overproduction, hormone underproduction, or structural abnormalities such as hyperplasia or neoplasms. Diagnostic evaluation commonly integrates hormone measurements, imaging characteristics, and clinical context to determine which adrenal pathway is affected. At the cellular level, steroidogenesis depends on enzymatic steps that can be altered by genetic defects or acquired disease processes, while medullary catecholamine secretion can be driven by tumor biology. These distinctions help explain why adrenal gland disorders can affect diverse body systems, including cardiovascular, metabolic, musculoskeletal, and reproductive functions.