This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Physiology
[{'content': 'Gastric secretions are increased by all of the following except \nSelect and explain. \nA. Somatostatin, B. Histamine, C. Vagal stimulation, D. Gastrin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Somatostatin released by D cells(located adjacent to G cells)inhibits gastrin secretion by G cells. -Vagal stimulation inhibits release of somatostatin & thus indirectly stimulates H+ secretion by removing inhibitory effect of somatostatin on parietal cells. -Histamine increases H+ secretion by acting on H2 receptors on parietal cells. -Gastrin is a hormone secreted by G cells into blood circulation. It stimulates secretory activity of parietal cells & chief cells. Reference: Medical Physiology, Indu Khurana', 'role': 'assistant'}]