This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urinary tract, Subject name: Pathology
Tamm Horsfall protein is produced by - 
Select and explain. 
A. Ureter, B. Collecting duct, C. Loop of Henle, D. Distal tubule
C: Loop of Henle
Answer: C: Loop of Henle 
Explanation: Various components observed on microscopic examination of the urine in renal disease are red cells, pus cells, epithelial cells, crystals and urinary casts. The casts are moulded into cylindrical shapes by passage along tubules in which they are formed. They are the result of precipitation of proteins in the tubule that includes not only albumin but also the tubular secretion of the Tamm Horsfall protein. The latter is a high molecular weight urinary glycoprotein normally secreted by ascending loop of Henle and DCT and probably has body defence function normally. Its secretion is increased in glomerular and tubular diseases Ref: Textbook of pathology Harsh Mohan 6th edition page 652