Representative image of Ki67 staining indicating a proliferating nucleus (arrow) and non-proliferating nuclei (arrow heads) Ki67 = red, insulin = green, nuclei = blue (a) Beta-cell proliferation (% Ki67 positive beta-cells/total cells) in non-transgenic (open bars) and hIAPP transgenic (solid bars) islets cultured for 48 hours in 16.7 mmol/l glucose with no drug (control), exendin-4 or diazoxide (b), no drug (control) or KCl (c). *p<0.05 vs. control, †p<0.05 vs. non-transgenic, n=6–9.