This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Renal physiology, Subject name: Physiology
The major prostanoid synthesized in kidney is 
Select and explain. 
A. PGE1, B. PGE2, C. PGI2, D. PGF2-alpha
B: PGE2
Answer: B: PGE2 
Explanation: PGE2 is the major prostanoid synthesized in the kidney. It is secreted by: RMICs (Renal Medullary Interstitial cells) Macula densa Cells in the collecting ducts. Prostacyclin (PGI2) and other prostaglandins are secreted by the aerioles and glomeruli. Renal Medullary interstitial cells (RMICs) and are specialized fibroblast-like cells which are major site of cyclooxygenase 2 (COX-2) and prostaglandin synthase (PGES) expression. Ref: Ganong&;s Review of Medical Physiology 26th editon Pgno: 662