PROBLEM TO BE SOLVED: To provide: a variant type natriuretic peptide B receptor that produces cGMP without stimulation of CNP； a gene encoding the receptor； a medicine that can effectively increase intracellular cGMP； a transgenic non-human mammal in which a gene encoding the receptor is transferred into the genome； and the like.SOLUTION: The variant type natriuretic peptide B receptor is one of the following polypeptides, or a salt thereof: (a) a polypeptide having a specific amino acid sequence； (b) a polypeptide that has an amino acid sequence whose one to several amino acids among the specific amino acids are deleted, added or replaced, and has an activity for producing cGMP without the stimulation of CNP； and (c) a polypeptide encoded by a DNA comprising a specific base sequence or by a DNA which hybridizes with a DNA composed of a base sequence complementary to the specific sequence in a stringent condition, and having an activity for producing cGMP without the stimulation of CNP.
