Fig. 4. Insulin and FGF2 induce the production of Islet1-expressing cells in the ganglion cell layer at the retinal margin. (A) Histogram demonstrating that the number of BrdU/Islet1-labeled cells in the inner nuclear layer at the retinal margin of insulin-treated eyes is increased between 1 and 4 days after the final injection. (B) Histogram demonstrating that the number of BrdU/Islet1-labeled cells in the ganglion cell layer is stimulated by insulin and FGF2. (C-E) Vertical sections of the retinal margin that were labeled for BrdU (green) and Islet1 (red). Tissues were obtained from eyes 4 days after the final dose of three consecutive daily injections of insulin and FGF2. Scale bar: in E, 50 µm in C-E. INL, inner nuclear layer; GCL, ganglion cell layer.