Introduction: C-type natriuretic peptide (CNP) selectively binds to the guanylyl cyclase coupled natriuretic peptide receptor (NPR)-B and exerts more potent antihypertrophic and antifibrotic properties. Elimination of CNP occurs mainly by neutral endopeptidase (NEP) and NPR-C.
Methods: We established a rat model of unilateral ureteral obstruction (UUO) to examine the continuous change of the CNP expression and to assess the correlations of NPR-B, NPR-C, NEP with CNP in the obstructed kidneys.
Results: The expressions of CNP mRNA and protein in the obstructed kidneys tended to be higher immediately after ligation and declined at later time points compared to sham-operated rats, measured by real-time polymerase chain reaction (PCR) and western blot analysis. Subsequent correlation analysis indicated that CNP mRNA was positively correlated with NPR-B mRNA (r=+0.673, p<0.05). In addition, the increased expression of NPR-C (r=-0.943 and -0.837 for mRNA and protein respectively, p<0.05) and NEP (r=-0.687 and -0.823 for mRNA and protein respectively, p<0.05) were accompanied by a signiﬁcant decline in CNP.
Conclusions: A high level of CNP may contribute to the elevated expression of NPR-B in the early phase of UUO. More interestingly, paradoxical expressions of NPR-C and NEP may account for the decline of CNP in the obstructed kidneys.
Keywords: C-type natriuretic peptide; natriuretic peptide receptor; neutral endopeptidase; obstructive nephropathy; unilateral ureteral obstruction.
© The Author(s) 2013.