Evolve Endocrine Practice Test 2026 – The All-In-One Guide to Mastering the Endocrine System!

Cushing's syndrome is primarily caused by an excess of cortisol in the body. This condition can occur due to various reasons, including a tumor in the adrenal glands that produces excess cortisol or a pituitary gland tumor that stimulates cortisol production. Elevated cortisol levels lead to various symptoms and signs such as weight gain, thinning skin, easy bruising, and hyperglycemia.

In contrast, the other choices are related to different endocrine disorders. For instance, a deficiency of thyroid hormones is associated with hypothyroidism, overproduction of insulin relates to hyperinsulinemia and conditions like insulinoma or type 2 diabetes, and autoimmune attacks on the pancreas primarily affect insulin production, leading to type 1 diabetes. Each of these conditions has distinct pathophysiological mechanisms and affects different hormones, which further underscores the specificity of Cushing's syndrome being caused by excess cortisol.