Non-coordinated variation of PC2 and PC1/3 expression in islets of control donors. Figure 8A and B illustrates islets of donor #6290 stained for insulin and either (A) PC2 or (B) PC1/3, respectively. Figure 8C and D illustrate islets of donor #6179 immunostained for insulin and either (C) PC2 or (D) PC1/3, respectively. Note that islets of donor #6290 have high PC2 and low PC1/3 levels, whereas donor #6179 has similar level of both enzymes. Bar: 30 µm. Abbreviations: PC2, proprotein convertase 2; PC1/3, proprotein convertase 1/3.