FIGURE 5. Analysis of -cells after pancreatectomy.

a, Increased BrdU incorporation after partial pancreatectomy (Px). Shown are representative islets from sham-operated or pancreatectomized mice, 7 days after operation. BrdU was administered continuously between operation and killing. Staining for BrdU (green), insulin (red) and DNA (blue). Original magnification, 400. Scale bar, 50 m. b, Origins of new -cells. Partial pancreatectomy was performed on tamoxifen-injected RIP–CreER;Z/AP mice, followed by BrdU administration for 2 weeks. Shown are confocal images of an islet stained for insulin (yellow), HPAP (red), BrdU (green) and DNA (blue). Four BrdU⁺ -cells are also HPAP⁺ (arrows), indicating that they were generated by replication of existing -cells. One BrdU⁺ cell is insulin-negative and HPAP^- (arrowhead); this is probably an or cell. Original magnification, 650.