Chronic hypersecretion of GH into the circulation, usually from a GH-secreting pituitary adenoma, is classically associated with acromegaly, a debilitating disease characterized by excessive skeletal growth, soft tissue enlargement, insulin resistance, and cardiovascular and gastrointestinal morbidities.1 Increased GH levels have also been implicated in cancer and diabetes.2–5 Pegvisomant, a GH analog, is the only clinically used antagonist of the GH receptor (GHR).6,7 However, other antagonists are in clinical trials or preclinical development. Here, GH1 is linked to pituitary gland adenoma.