Figure 2

Pdx1 expressing ES cell-derived IPCs are glucose responsive. (a) Insulin secretion by 1 × 10⁶ IPCs plated in triplicates in six-well plates and generated using all the four differentiation protocols was evaluated by ELISA and expressed relative to the protein content of the cells. The results indicate that generation of IPCs using protocol D by eliminating the nestin selection stage significantly improves the generation of IPCs. The values represent mean ± SD (n = 3) where ***P < 0.0001 vs other groups by one-way ANOVA with Tukey’s multiple pairwise comparison. (b) For testing glucose stimulated insulin secretion, 5 × 10⁴ IPCs were plated in 24-well plates in triplicates in the presence of 2.8 mM glucose (LG), 2.8 mM glucose + 100 μM tolbutamide (LG + TB), 20 mM glucose (HG) or 20 mM glucose + 50 μM nifedipine (HG + NI). The insulin secretion was monitored by an ultrasensitive ELISA. The values represent mean ± SE (n = 3) and all data were tested for significance with Student’s t- test or one way ANOVA where applicable. In all cases, *P < 0.05 was considered statistically significant.