This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidneys and Body Fluids, Subject name: Physiology
[{'content': 'Renin is synthesized as a large preprohormone: Renin is secreted by which among the following? \nSelect and explain. \nA. PCT, B. DCT, C. Collecting duct, D. Juxtaglomerular apparatus', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. D. Juxtaglomerular apparatusActive renin:In the juxtaglomerular apparatus and is formed in the secretory granules of the granular cells. Only known function of its is to cleave the decapeptide angiotensin I from the amino terminal end of angiotensinogen i.e. renin substrate.', 'role': 'assistant'}]