This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bleeding from the GUT and diseases of esophagus, Subject name: Medicine
[{'content': "A vasopressin analogue does not produce therapeutic effect through vasopressin V2 receptor in which of the following:- \nSelect and explain. \nA. Central diabetes insipidus, B. Bleeding oesophageal varices, C. Type I von Willoebrand's disease, D. Primary nocturnal enuresis", 'role': 'user'}, {'content': 'Answer: B \nExplanation: In choice A and D vasopressin stimulates V2 receptors and leads to reduction in polyuria due to re-absorbtion of water the water channels. DDAVP induces vWF secretion by binding to V2R and activating cAMP-mediated signaling in endothelial cells and controls bleeding in vWD. Vasopressin exes vasoconstrictive effect on splanchnic circulation VI receptors Receptor of vasopressin Location Action V1 G protein - coupled phoshatidyl inositol/ calcium Vascular smooth muscle, platelet, hepatocytes, myometrium Vasoconstriction, myocardial hyperophy, platelet aggregation, glycogenolysis, uterine contraction V3 G protein -coupled, phosphatidyl inositol/calcium Anterior pituitary gland Releases ACTH, prolactin, endorphins V2 Adenyl cyclase/ cAMP Basolateral membrane of collecting duct, vascular endothelium and vascular smooth muscle cell Inseion of AQP - 2 water channels into apical membrane, induction of AQP - 2 synthesis, releases von willebrand factor and factor VIII, vasodilation', 'role': 'assistant'}]