This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'Which of the hormones is secreted by alpha-cells in the pancreas in response to low blood glucose levels? \nSelect and explain. \nA. Insulin, B. Glucagon, C. Epinephrine, D. Somatostatin', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Glucagon, is a 29-amino acid polypeptide hormone secreted by the -cells of the islets of Langerhans, which plays an impoant role in the regulation of glucose homeostasis by producing antagonistic effects on insulin action. Glucagon release is inhibited by hyperglycemia (high blood glucose levels) and stimulated by hypoglycemia (low blood glucose levels). Ref: Molina P.E. (2010). Chapter 7. Endocrine Pancreas. In P.E. Molina (Ed), Endocrine Physiology, 3e.', 'role': 'assistant'}]