Differential localization of prostaglandin E receptor subtypes in human kidney

Four prostaglandin E2 (PGE2) receptors designated EP1, EP2, EP3, and EP4 have been pharmacologically identified, cloned, and sequenced. The present studies determined the intrarenal distribution of these EP-receptor subtypes in human kidney using in situ hybridization with riboprobes for the human EP receptors. mRNA for the phosphatidylinositol hydrolysis-coupled EP receptor was highly expressed in cortical, outer medullary, and inner medullary collecting duct. RNA for the Gi-coupled EP3 receptor was primarily expressed in the cortical and outer medullary collecting duct, as well as in the medullary thick ascending limb; however, it was absent from the inner medullary collecting duct. Expression of mRNA for EP1 and EP3 in connecting segment could not be excluded. There was no expression of the GS-coupled EP2 receptor mRNA detected in human kidney by in situ hybridization; however, mRNA for the GS-coupled EP4 receptor was highly expressed in the glomerulus. These studies demonstrate distinct regions of intrarenal expression for the different EP receptors and suggest that each receptor subtype may modulate different aspects of renal function in humans.