File:Relationship between developing islet and duct cells..jpg

English: Co-immunofluorescence staining of Neurog3 (green) and the duct marker Muc1 (red), in E13.5 mouse pancreas, reveals the intimate relationship between islet precursor cells and duct-like structures A. This can also be appreciated from co-immunohistochemistry for insulin (red) and the duct marker cytokeratin-19 (brown) on sections of human fetal pancreas B-D. At early gestational ages (8.5-10.5 weeks post-coitum), β-cells are located within ductal structures, and co-express insulin and CK19. At later ages (14 wpc-adult), CK19-negative β-cells aggregate outside the ductal network. Panels B-D are adapted from Piper et al (Piper et al. (2004). (B-D) copyright Society for Endocrinology (2004), reproduced by permission.