Abstract: New peptidic derivatives having the general formula (I): X.sub.1 X.sub.2 X.sub.3 Ile X.sub.5 X.sub.6 wherein X.sub.1 is hydrogen, a rest of histidin, of acetyl-histidin or of D-histidin, X.sub.2 is a rest of alanin, of leucin, of tryptophan, of phenylalanin as well as their homologs in D series, X.sub.3 is a rest of alanin as well as its D series homolog, X.sub.5 is a rest of isoleucin, of alanin, of valin, of norleucin, of leucin and of aspanic acid as well as their D series homologs, X.sub.6 is a rest of tryptophan, of leucin, of isoleucin, of norleucin and their D series homologs, method for the preparation and application of such new derivatives as medicaments.