The present invention relates to peptides which are highly biologically and pharmacologically active as therapeutic drug for the treatment of diseases related to hypertension, especially in medical interventions involving dilatation and remodeling of arterial blood vessels, either in the pulmonary or in the systemic circulation. The peptides which can be used according to the invention for the treatment of said diseases comprise at least one specific highly conservative amino acid residue sequence which seem to play an important role in connection with pulmonary and arteriolar hypertension events. It could be shown that the known naturally occurring peptides “vasoactive intestinal peptide (VIP)” and “pituitary adenylate cyclase-activating polypeptide (PACAP)”, having these specific sequences are potent drugs which can be successfully used for treatment of primary pulmonary hypertension (PPH), secondary pulmonary hypertension (SPH), and hypertension of the systemic circulation. Furthermore, the present invention discloses pharmaceutical compositions useful for treatment of PPH, SPH, and hypertension of the systemic circulation within said methods.
