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
Function of vasopressin 
Select and explain. 
A. Absorption of water in PCT, B. Absorption of water in loop of Henle, C. Absorption of water in collecting duct, D. Absorption of Na+ in PCT
C: Absorption of water in collecting duct
Answer: C: Absorption of water in collecting duct 
Explanation: Vasopressin- a hormone secreted by cells of the hypothalamic nuclei and stored in the posterior pituitary for release as necessary; it stimulates contraction of the muscular tissues of the capillaries and aerioles, raising the blood pressure, and increases peristalsis, exes some influence on the uterus, and influences resorption of water by the kidney tubules, resulting in concentration of urine.Ref: Ganong&;s review of medical physiology; 24th edition; page no:-303