Synonyms: Atriopeptin-21(rat),N-(N2-acetyl-L-arginyl)-5-D-alanine-14-L-leucine-16-D-alanine-18-D-alanine-21a-(N-methyl-L-phenylalanine)-21b-L-arginine-21c-D-tyrosine-21d-L-prolinamide-;1,2-Dithia-5,8,11,14,17,20,23,26,29,32,35,38,41,44,47,50-hexadecaazacyclotripentacontane,cyclic peptide deriv.; ANP 270; NNC 700270