This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Physiology
[{'content': 'Where does ADH not act? \nSelect and explain. \nA. PCT, B. Collecting duct., C. Collecting tubules, D. DCT', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Vasopressin is a hormone secreted by cells of the hypothalamic nuclei and stored in the posterior pituitary for release as necessary; its stimulates contraction of the muscular tissues of the capillaries and aerioles, raising the blood pressure, and increases peristalsis, exe some influence on the uterus, and resorption of water by the kidney tubules, resulting in concentration of urine. Its rate of secretion is regulated chiefly by the osmolarity of the plasma.Ref: Ganong&;s review of medical physiology; 24th edition; page no:-303', 'role': 'assistant'}]