BNP is mainly expressed by ventricular myocardium in response to volume overload and increased filling pressure. The BNP gene encodes a 134-amino acid preproBNP precursor, which is converted to 108-amino acid proBNP by the proteolytic cleavage of a 26-amino acid signal peptide (26). ProBNP is further cleaved into the the N-terminal fragment of proBNP (NTproBNP, 1-76) and the C-terminal region biologically active BNP hormone (77-108) (30) also named BNP-32 and additional C-terminal fragments (cf. http://www.uniprot.org/uniprot/P16860#PRO_0000001532; (Kambayashi et al., 1990; Nakagawa et al., 2019; Sudoh et al., 1989).