Fig. 1.
GLP-1-Tf exhibited similar efficacy but lower potency than native GLP-1, was insulinotropic, and had a prolonged half-life. A, stably transfected CHO/GLP-1R cells were treated with increasing concentrations of native GLP-1 and GLP-1-Tf for 30 min followed by assay of intracellular cAMP (n = 2 separate experiments). B, isolated rat islets (n = 40/treatment group) were treated with increasing concentrations of native GLP-1 or GLP-1-Tf for 1 h at 37°C, and the insulin secreted into the buffer was assayed (n = 4 different islet preparations). C, rat insulinoma (RIN1046-38) cells were treated with increasing concentrations of native GLP-1 and GLP-1-Tf for 1 h at 37°C, and the insulin secretion into the buffer was assayed (n = 4 separate experiments). D, cynomolgus monkeys were injected with GLP-1-Tf (2.25 mg/kg) subcutaneously and intravenously, and their serum was assayed at the time points shown (n = 4 animals).