Detection of C-type natriuretic peptide (CNP) transcript in the rat heart and immune organs

Previous studies suggested the expression of mRNA, coding for CNP,
exclusively in the central nervous system. In the present study,
using the polymerase chain reaction (PCR) technique instead of the
less sensitive Northern blot hybridization, CNP-specific sequences
have also been detected in rat atria and ventricles of the heart as
well as in organs of the immune system (thymus, spleen and lymph
nodes). Parallel PCR-assays documented ANP-mRNA in these tissues.
To verify specificity of the PCR-products, Southern blots have been
hybridized with a third internal oligonucleotide and amplification
products have been sequenced. The relative level of CNP-mRNA in
these tissues was estimated to be in the range of 1-9% of total
brain CNP transcripts. The results suggest that the peptide may
have a peripheral as well as a central site of action. In light of
its pronounced effect on cell proliferation, particular interest
should focus on a possible role of CNP in the immune system.