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
Renin is synthesized as a large preprohormone: Renin is secreted by which among the following? 
Select and explain. 
A. PCT, B. DCT, C. Collecting duct, D. Juxtaglomerular apparatus
D: Juxtaglomerular apparatus
Answer: D: Juxtaglomerular apparatus 
Explanation: 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.