Synthesis and in vitro characterization of new growth hormone secretagogues derived from ipamorelin with dipeptidomimetic N-terminals

The structural requirements for N-terminal features for the minimal structu re of growth hormone secretagogues derived from ipamorelin are investigated . It is found, that incorporation of nonpolar peptidomimetic amino acids at the N-terminal can replace the Aib-His moiety and lead to compounds with h igh in vitro potency with respect to their growth hormone secretagogue prop erties. New unnatural amino acids with double bonds, ether-linkages, and 1, 3-phenylene-moieties in the backbone proved to be valuable dipeptidomimetic s. Using them, growth hormone secretagogues with high potencies were obtain ed. (C) Elsevier, Paris.