CELLULAR EXPRESSION OF ANGIOTENSIN TYPE-1 RECEPTOR MESSENGER-RNA IN THE KIDNEY

Angiotensin II has multiple renal effects that are important in the re gulation of renal hemodynamics and electrolyte secretion, and binding sites for angiotensin II have been demonstrated in different cells of the kidney. In the present study the cellular localization of mRNA for the angiotensin type 1 (AT1) subtype of the angiotensin II receptor w as studied in adult rat kidney using a cRNA probe and in situ hybridiz ation. Strong labeling was demonstrated in tubule cells of the inner a nd outer stripe of the outer medulla. In emulsion-dipped sections, cou nter-stained with hematoxylin-eosin, labeling was identified in segmen t S3 of proximal tubules and in the thick ascending limb of loop of He nle (mTAL). The results suggest expression of AT1-receptor mRNA with a distinct compartmentalization within the nephron.