Endothelin (ET)-related peptide hormones, ET-1, vasoactive intestinal contractor (VIC), ET-2 and ET-3, have multiple physiological roles including vasoconstriction. To reveal the structural diversity of the precursor proteins of the ET family, cDNAs, cross-hybridizing with ET-1 and VIC probes, were cloned from the mouse intestine library. The deduced protein is a 214-amino acid precursor of mouse ET-3, preproendothelin-3 (PPET-3), which is the counterpart of the hypothalamus-, not placenta-, derived human PPET-3. Sequence identities of PPET-3 amino acids of mouse with human and rat are 65% over 194 amino acids and 65% over 214 amino acids. Phylogenetic analysis of the precursor proteins for ET-1, VIC and ET-3 suggest that members of the ET family are distantly related and probably descended from a common ancestral gene.