What is a characteristic of Graves' disease?

Graves' disease is primarily characterized by hyperthyroidism, which is an overproduction of thyroid hormones by the thyroid gland. This condition leads to an accelerated metabolism, resulting in symptoms such as weight loss, increased heart rate, anxiety, tremors, and heat intolerance. The hyperthyroid state in Graves' disease is often caused by an autoimmune response that stimulates the thyroid gland to produce excessive amounts of these hormones. As such, the defining feature of Graves' disease correlates with the excess thyroid hormones circulating in the body, distinguishing it from other disorders that might present with different hormonal imbalances, such as insulin resistance or elevated cortisol levels.

The other options relate to conditions not typical of Graves' disease or to unrelated endocrine issues. Low blood pressure is not characteristic of hyperthyroid states, which often accompany increased blood pressure. Insulin resistance primarily relates to metabolic disorders like type 2 diabetes rather than thyroid function. Elevated cortisol levels are more indicative of conditions like Cushing's syndrome, not Graves' disease.