Co-expression of type 1 angiotensin II receptor (AT1R) and renin mRNAs in juxtaglomerular cells of the rat kidney.

Physiological and ligand binding studies have shown that Angiotensin II (AII) exerts various functions along different segments of the nephron, via the type-1 receptor (AT1R), resulting in the control of glomerular filtration rate (GFR) and water and salt homeostasis. We have used 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 hybridization with a renin cRNA probe, also co-express AT1R mRNA. The co-expression of AT1R and renin mRNAs in the same cells documents visually the direct feedback control of AII on renin secretion. AT1R mRNA was also present in known target cells for AII: proximal convoluted tubule, mesangium and vasa recta.