Truncated glucagon‐like peptide‐1 (proglucagon 78–107 amide), an intestinal insulin‐releasing peptide, has specific receptors on rat insulinoma cells (RIN 5AH)

Abstract

We studied binding of ¹²⁵I‐labelled truncated‐glucagon‐like peptide‐1 (proglucagon 78–107 amide) to a cloned rat insulin‐producing cell line, RIN 5AH, in monolayer culture. Interaction of the peptide with pancreatic insulinoma cells was saturable and time dependent. Half‐maximal binding was obtained when the cells were incubated in the presence of 3.3 × 10⁻⁹ mol/l unlabelled truncated‐glucagon‐like peptide‐1 (proglucagon 78–107 amide). Neither glucagon, full‐length glucagon‐like peptide‐1 (proglucagon 72–107 amide) nor gastric inhibitory peptide competed for binding in concentrations up to 10⁻⁶ mol/l.