Differential absorption and distribution of epidermal growth factor and insulin-like growth factor in diabetic NOD mice

Previous studies have shown that absorption of growth factors occurs throug h the gastrointestinal tract and the oral cavity. The non-obese diabetic (N OD) mouse, a model for spontaneous development of type 1 insulin-dependent diabetes (IDDM), was evaluated for the absorption and systemic distribution of growth factors. Radiolabeled epidermal growth factor (EGF) and insulin- like growth factor, type I (IGF-T), were administered by gavage into the st omach or by lozenge into the sublingual vasculature of either diabetic or n ondiabetic mice. After a time dependent uptake, the levels of absorption an d distribution through the tissues were measured. A similar time course of EGF absorption following gavage administration was determined for NOD and C 57BL/6 mice, with a maximum tissue distribution by 30-min post infusion. Di abetic NOB mice showed similar levels of IGF uptake and tissue distribution compared with nondiabetic NOD and normal healthy C57BL/6 mice, whether adm inistered by gavage or sublingual lozenge. On the other hand, gavage uptake and tissue distribution of EGF was significantly higher in diabetic mice w hen compared to sublingual administration in nondiabetic NOD or C57BL/6 hea lthy control mice. These findings suggest that the overall potential uptake and distribution of saliva-derived growth factors in systemic wound-healin g processes is retained with diabetes onset, and may offer a new avenue to treating this complication of diabetes. (C) 2001 Elsevier Science Inc. All rights reserved.