Natriuretic peptide precursor C is cleaved to the 22 amino acid peptide C-type natriuretic peptide (CNP). Unlike ANP and BNP, CNP does not have direct natriuretic activity. This is because CNP is a selective agonist for the B-type natriuretic receptor (NPRB) whereas ANP and BNP are selective for NPRA.

Recent evidence from rodents and humans shows that C-type natriuretic peptide (CNP) plays an essential role in endochondral bone growth. A stable product of proCNP, amino-terminal proCNP (NT-proCNP), which unlike CNP is readily measurable in human and ovine plasma. NT-proCNP levels in blood show a strong association with growth velocity and markers of bone formation and may well serve as a useful marker of growth plate activity in humans and other mammals.