<prompt> The major prostanoid synthesized in kidney isPGE1PGE2PGI2PGF2-alpha  <response>: 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 