NANP Board Practice Exam

Where is glucagon produced?

1. Adrenal medulla

2. Alpha cells of pancreatic islets

3. Liver

4. Thyroid gland

The correct answer is: Alpha cells of pancreatic islets

Glucagon is a vital hormone primarily produced by the alpha cells of the pancreatic islets, also known as the islets of Langerhans. These specialized cells release glucagon in response to low blood sugar levels, signaling the liver to release stored glucose into the bloodstream, thereby raising blood sugar levels. This process is crucial for maintaining homeostasis, especially during fasting or between meals when blood glucose levels might drop. The other choices relate to locations or functions that do not involve the production of glucagon. The adrenal medulla primarily produces catecholamines such as adrenaline and noradrenaline, which play roles in the body's fight-or-flight response. The liver, while it does play a significant role in glucose metabolism, is not the site of glucagon production itself. Instead, it responds to glucagon. The thyroid gland is responsible for producing thyroid hormones, which regulate metabolism and are unrelated to glucagon production. Understanding these distinctions highlights the specific role of the alpha cells in the regulation of glucose metabolism.