Figure 3.

Effects of proglucagon products on insulin secretion in the isolated‐perfused rat pancreas. Pancreases isolated from Sprague‐Dawley rats were perfused with 5‐mmol L⁻¹ glucose and either 30 pmol min⁻¹ hGLP‐1 7–36 (A, B), 3 or 30 pmol min⁻¹ rGRPP (C,D), 3 or 30 pmol min⁻¹ rGRPP‐LP (E, F), or vehicle (A–F, solid lines). Glucose was increased to 20 mmol L⁻¹ at 20 min (shaded area): n = 5/group. hGLP‐1 7–36 increased insulin secretion at 5‐mmol L⁻¹ glucose and at 20‐mmol L⁻¹ glucose compared with the control (A). By contrast, rGRPP and rGRPP‐LP all inhibited GSIS (C,E). Lactate output (B, D, F) remained at a constant level throughout the perfusion in all groups, and there were no significant differences between the groups.