The adrenal glands are two small, triangular structures situated atop each kidney. These glands are part of the endocrine system, producing hormones that regulate numerous bodily functions. When facing a medical condition requiring the removal of one gland, many people wonder if normal function can be maintained. The answer is reassuring: the body is well-equipped to handle the loss, and individuals typically live a full, healthy life without continuous hormone replacement therapy.
The Essential Functions of the Adrenal Glands
The adrenal glands are structurally divided into two main parts that produce different types of hormones. The outer layer, the cortex, synthesizes steroid hormones. These include the glucocorticoid cortisol, which manages the body’s response to stress, regulates metabolism, and helps control blood pressure. The cortex also produces the mineralocorticoid aldosterone, which regulates blood pressure and maintains the balance of sodium and potassium. The inner portion, the medulla, produces catecholamines—epinephrine and norepinephrine—which mediate the body’s immediate “fight or flight” response.
How the Remaining Gland Maintains Homeostasis
The ability to function normally with only one adrenal gland is due to glandular reserve and redundancy. When one gland is removed, the remaining gland is signaled to increase its activity to compensate for the loss. This physiological adaptation ensures that the total output of necessary hormones remains within the normal range. This increase in activity is achieved through compensatory hypertrophy. The remaining adrenal gland physically enlarges as its constituent cells increase in size, enhancing its hormone-producing capacity. This cellular enlargement is concentrated primarily in the adrenal cortex. This adaptive capacity means that, under typical, non-stressed circumstances, the single gland is sufficient to prevent long-term hormone deficiency and maintain normal bodily homeostasis.
Medical Reasons for Single Adrenal Gland Status
The most common reason an individual has only one functioning adrenal gland is a unilateral adrenalectomy, the surgical removal of one gland due to a diagnosed medical condition. In many cases, the surgery is performed to remove a functional tumor causing an overproduction of hormones. Examples include an aldosteronoma, which secretes excessive aldosterone, or a pheochromocytoma, which releases high amounts of catecholamines. Other reasons for removal include large, non-functional masses discovered incidentally during imaging. Removal is also necessary for primary adrenal cancer (adrenocortical carcinoma) or when cancer has spread from a primary site elsewhere in the body, such as the lung or breast.
Long-Term Medical Monitoring and Management
While a single adrenal gland is capable of sustaining life, long-term monitoring is often necessary, especially in the initial period following surgery. The primary medical concern is the risk of postoperative adrenal insufficiency (AI), particularly if the removed gland was previously producing high levels of cortisol (Cushing’s syndrome). This hormone excess can suppress the function of the remaining gland, requiring a temporary recovery period. Regular follow-up with an endocrinologist is recommended to assess the remaining gland’s reserve capacity, often using the ACTH stimulation test. Patients who had a cortisol-secreting tumor may need temporary glucocorticoid replacement therapy until the remaining gland fully resumes its normal function.
Individuals with a single gland must be educated on the necessity of “stress dosing” during severe illness, trauma, or major surgery. These high-stress events demand a temporary, significant increase in glucocorticoid production that the single gland might not immediately meet. An inability to mount this stress response can lead to an adrenal crisis, characterized by extreme fatigue, dizziness, and low blood pressure.