ProRenin/Renin Receptor is Expressed in the Collecting Duct of Normal Rat Kidney

Abstract

Tubular renin is present in principal cells of collecting ducts (CD) of human, mouse and rat kidneys. The recent cloned(pro)renin renin receptor (PRR), is localized in brain, lung, heart and kidney, and binds renin or (pro)renin, thus leading to increased renin catalytic activity, or allowing (pro)renin to become fully active. Within the kidney, PRR is expressed by glomerular mesangial cells, podocytes, and renal arteries. The presence of PRR in CD might be important for potential generation of tissue angiotensin peptides in the terminal nephron segment. We investigated the immunolocalization of PRR in normal rat kidneys. Immunoperoxidase technique was performed by using a goat anti‐PRR antibody on 4% paraformaldehyde fixed normal rat perfused kidney sections. As described, positive immunostaining of PRR was visualized in mesangial cells, podocytes, and smooth muscle cells of cortical and medullary renal arteries. Interestingly, positive PRR immunoreactivity was also observed in the apical aspects of the cortical and medullary CD cells. Our results demonstrate the presence of PRR immunoexpression in cortical and medullary CD cells. Co‐expression of renin and PRR in the distal nephron suggests that renin or (pro)renin secreted by principal cells of CD into the tubular lumen anchors to the PRR allowing increased efficiency of Ang I formation contributing to angiotensin peptide generation in the CD.