Insulin-producing cells are bi-potential and differentiatorsprior to proliferation in early human development

Figure 1 Staining by hematoxylin-eosin in embryonic pancreas exhibited pancreatic primary duct at 6 wk gestation. A: The first-order bifurcation; B: The second-order bifurcation; C: The third-order bifurcation. Arrows show the duct beginning bifurcation. Bars = 200 μm.

Figure 2 Expression of insulin in fetal pancreas. Immunohistochemical staining is shown for insulin in pancreatic duct epithelium of 11 wk gestation. Arrow shows β-cell has differentiated before migration from duct. Bars = 50 μm.

Figure 3 Immunohistochemical double staining in fetal pancreas. A: For insulin glucagon (indigo) and insulin (scarlet); B: For somatostatin (indigo) Insulin (scarlet). Arrows showing the duct epithelia cell co-expressing insulin, glucagon or somatostatin at 11 wk gestation. Bars = 200 μm.

Figure 4 Double immunofluorescence staining in fetal pancreas insulin (FITC label, green) and nestin (Cy3 label, red). A: At 11 wk, bar = 100 μm; B: At 14 wk, bar = 100 μm. Arrow shows that islet has formed and insulin-producing cells express nestin.