COEXPRESSION OF TYPE-1 ANGIOTENSIN-II RECEPTOR (AT(1)R) AND RENIN MESSENGER-RNAS IN JUXTAGLOMERULAR CELLS OF THE RAT-KIDNEY

Physiological and ligand binding studies have shown that Angiotensin I I (AII) exerts various functions along different segments of the nephr on, via the type-1 receptor (AT1R), resulting in the control of glomer ular filtration rate (GFR) and water and salt homeostasis. We have use d the recently cloned AT1R cDNA to localize, by in situ hybridization, the cells expressing AT1R mRNA in the rat kidney. On serial sections, juxtaglomerular (JG) renin secreting cells, identified by hybridizati on with a renin cRNA probe, also co-express AT1R mRNA. The co-expressi on of AT1R and renin mRNAs in the same cells documents visually the di rect feedback control of All on renin secretion. AT1R mRNA was also pr esent in known target cells for AII: proximal convoluted tubule, mesan gium and vasa recta.