Selective stimulation of insulin secretion by CCK-4 analogues having N-terminal modifications

Summary Synthetic analogues of CCK-4 in which Trp¹ was replaced by D-Pro (peptide I), Thz (peptide II) and ΔPro (peptide III) have been studied for their insulin and glucagon releasing activities from the islets of Langerhansin vitro. Peptide I has been found to be the most potent insulin releaser among the three analogues and its activity is comparable to that of CCK-4. Unlike CCK-4, its three analogues (peptides I–III) do not stimulate the release of glucagon with basal concentration of glucose in the medium. However, with increasing glucose concentration, all the three analogues potentiate the glucose stimulus for insulin release. C.D.R.I. Communication n ^o 4735.