Which disorder is characterized by low levels of adrenal hormones?

The disorder characterized by low levels of adrenal hormones is Addison's disease. This condition, also known as primary adrenal insufficiency, occurs when the adrenal glands do not produce sufficient amounts of cortisol and sometimes aldosterone. The lack of these vital hormones can lead to a variety of symptoms, including fatigue, weight loss, low blood pressure, and hyperpigmentation of the skin.

Addison's disease can result from autoimmune destruction of the adrenal glands, infections, or other factors that compromise adrenal function. In contrast, the other disorders listed are associated with different endocrine abnormalities. For example, Graves' disease results in an overproduction of thyroid hormones, Cushing's syndrome is characterized by excessive cortisol levels, and diabetes mellitus primarily involves issues with insulin secretion or action. Therefore, Addison's disease is the only condition among the options that specifically reflects low adrenal hormone levels.