Figure 4.

Suppression of extracellular‐signal‐regulated kinase 5 (ERK5) activation impairs gestational beta‐cell proliferation. At gestational day 15, the mice were analysed. A, The random blood glucose in pregnant mice that had received BIX02189 (BIX) and in the pregnant mice that had received saline (saline) was determined. B, The glucose tolerance in BIX and saline‐treated from pregnant mice at gestational day 15 (PRG) and control non‐pregnant littermates (NOP) was determined by IPGTT. C, Beta‐cell mass. D‐E, Beta‐cell proliferation was determined by Ki‐67⁺ beta cells, shown by quantification of Ki67⁺ INS + cells (D) and representative images (E). A square inset in white was shown for each panel in E. F‐G, Beta‐cell apoptosis was determined by terminal deoxynucleotidyltransferase‐mediated dUTP‐biotin nick end labelling (TUNEL) + beta cells, shown by quantification of TUNEL + INS + cells (F) and representative images (G). *P < .05. NS, no significance, n = 5. Scale bars are 50 μm.