Therapeutically active polypeptides or acid addition salts thereof and a process for producing such compounds

摘要

Polypeptide derivatives of the formula: a-x-y-arg-leu-d wherein x represents a bond, a single amino acid or a peptide having up to 10 amino acids in the chain, y represents gln- glu or glu, a represents hydrogen or a small protective group for the alpha -amino group in the N-terminal amino acid, d represents -NR1R2, wherein R1 and R2 are selected from the group consisting of hydrogen, C1-C6 alkyl and C3-C8 cycloalkyl, or R1 and R2 together with the attached nitrogen atom form a heterocyclic group optionally containing an additional hetero atom, or d represents -OR3, wherein R3 is selected from the group consisting of hydrogen, C1-C6 alkyl, C3-C8 cycloalkyl, benzyl, substituted benzyl, phenacyl, phthalimidomethyl, beta -methylthioethyl, and 4-picolyl or acid addition salts of such peptides, may be produced by peptide synthesis methods known per se. The polypeptides potentiate the glucose stimulated secretion of insulin from Langerhans's islets.