Wild-type (wt/het) and Mitfce/ce mutant islets consist of insulin, glucagon, somatostatin, and PP cells (A). B: Average β-cell area is unchanged in Mitfce/ce animals; n = 3. C: Quantitative RT-PCR measurement of pancreatic hormone levels in Mitf mutant and wild-type islets (n > 5 per genotype.) The data were normalized to HPRT mRNA levels and are presented as relative to control (set as 1). t test, *P < 0.05, ***P < 0.001.