Synthesis of [8-norleucine]somatostatin-28

Because of the high tendency of natural and synthetic somatostatin-28 to S-oxide formation at methionine-8 via air-oxidation, the 8-norleucine analogue was prepared following the synthetic route previously elaborated for the parent methionine peptide. [Nle8]-somatostatin-28 was obtained at a high degree of purity as judged by different analytical assays. It was found to possess the identical stimulatory effect on amylase release from pancreatic acini as the natural peptide extracted from porcine intestine.