Expression and Co-Localization of C-Type Natriuretic Peptide and Endothelin in Human Kidney

Abstract C-type natriuretic peptide (CNP) is an endothelium-drived vasorelaxing factor which is present in human plasma, urine and renal epithelial cells. Endothelin (ET) is a potent renal and systemic vasoconstrictor and sodium regulating peptide. To date, the localization of C-type natriuretic peptide and endothelin gene expression in human kidney remains poorly defined. We determined the co-localization of C-type natriuretic peptide and endothelin mRNA in normal human kidney using in situ hybridization (ISH) with synthesized human C-type natriuretic peptide or human endothelin oligonucleotide probes together with immunohistochemical staining (IHCS) with human CNP-22 and ET-1 antibodies with no crossreactivity. The sections treated with nonimmune rabbit serum (NRS) demonstrated no immunoperoxidase activity. Human renal tissue (n=7) was obtained from biopsy of normal cadaveric donor kidneys and normal autopsy specimens. In situ hybridization (Figure 1) demonstrated that C-type natriuretic peptide and endothelin mRNA presence in human kidney which was localized to proximal and distal tubes with similar intensities.