Localized cellular proliferation in the pancreatic ductal lining upon α-cell-specific <i>Arx</i> loss.

(A–I) A 10-day BrdU pulse-chase was performed in 3 month-old IndGlu-ArxKO animals subjected to a 2 month-long Dox treatment. An increase in the number of proliferating cells was thereby noted, most of these being detected in the lining of the duct close to the non-β-cell cluster (B–C, E–F, H–I compared to A, D, G). Of note, the ductal epithelium was found thickened in mutant pancreata, suggesting an increased ductal cell number (C, F, I). (J–L) The investigation of cell proliferation in 13 month-old Glu-ArxKO animals also revealed increased numbers of proliferating cells (K–L) compared to controls (J), as assayed by the expression of the proliferation marker KI67. These were again mainly found in the ductal lining adjacent to the islets (K–L). For the purpose of clarity, islets are outlined in dashed yellow lines in selected photographs.