Organ-specific mRNA distribution of C-type natriuretic peptide in neonatal and adult mice.

C-type natriuretic peptide (CNP) is described as an endothelium-derived vasodilator and a growth inhibitor of vascular smooth muscle cells. In the present study, CNP mRNA was quantified by RNase-protection assay to elucidate organ distribution of CNP in neonatal and adult mice. In adult mice, the highest CNP expressions were detected in uterus and ovary, which exceeded the CNP concentrations of forebrain and brainstem. In contrast, neonatal mice showed highest CNP-mRNA levels in forebrain and brainstem with lower levels in skin, tongue, heart, lung, thymus, skeletal muscle, liver, kidney, stomach, and skull. Thus, CNP-expression pattern diminishes during postnatal development. The observation that the expression level of CNP mRNA is 2.2-fold higher in the adult forebrain compared to the neonatal forebrain allows a comparison between all neonatal and adult organs.