This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Physiology
Lower esophageal sphincter pressure is increased by all of the following substances, EXCEPT: 
Select and explain. 
A. Gastrin, B. Vasopressin, C. Glucagon, D. Secretin
D: Secretin
Answer: D: Secretin 
Explanation: The lower esophageal sphincter, a physiologic entity but not an anatomic structure, plays an impoant pa in preventing gastroesophageal reflux. Neural, hormonal, myogenic, and mechanical factors influence the tone of the sphincter. Gastrin, vasopressin, glucagon, adrenergic agonists, and cholinergic agents increase the pressure. Secretin has the opposite effect REF: GUYTON 12TH ED