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: Physiology
[{'content': 'Gastrin is produced by: \nSelect and explain. \nA. Pancreas., B. Gastric antral cells., C. Pituitary., D. All.', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Gastrin is a hormone which is produced by G cells in the lateral wall of glands in the antral portion of gastric mucosa. It is also found in pancreatic islets in fetal life, gastroinomas of pancreas, and pituitary gland, hypothalamus, medulla oblongata and in vagus and sciatic nerves.\nActions-\n- Stimulation of gastric acid and pepsin secretion.\n- Stimulates growth of mucosa of stomach, small and large intestine.\n- Promotes gastric emptying\n- Stimulation of insulin secretion.', 'role': 'assistant'}]