Ghrelin lineage-labeled cells are frequently found in the pancreatic exocrine and ductal compartments in neonates.

Ghrelin-lineage labeled Tom+ cells predominantly localize to the islet periphery (a). Approximately 50% of the embryos analyzed contained ghrelin-labeled cells within the amylase+ acini clusters (b). This phenomenon is preferentially observed in juxta-duodenal regions of the ventral pancreas. (c) Ghrelin-lineage labeled cells that co-expressed ductal markers were also identified in the same animals. In Neurog3^−/− pancreata (d–f), which are almost completely devoid of endocrine hormone-producing cells, we could detect a small number of ghrelin-expressing and lineage labeled cells (d). We also detected ghrelin descendants in the exocrine (e) and ductal tissue (f) of Neurog3^−/− embryos. (g–j) In Nkx2.2^−/− mice, a subset of Ppy- (g) and glucagon-expressing cells (h) are still derived from ghrelin-expressing cells. Ghrelin-labeled cells are also detected in the exocrine and ductal compartment of Nkx2.2^−/− animals (i–j). The frequency and magnitude of lineage labeling of these cells were not significantly different from wild type pancreas. a, d and e are representative images of at least 3 pancreata. b, c, f, g, h, i, j are representative image of at least 3 embryos in which we detected labeled cells localized to the exocrine and ductal pancreatic tissue. All images are from Ghrl-Cre;R26-TOM P0 pancreas in the indicated genetic backgrounds. DAPI staining was used to visualize the nuclei. Scale bar: all panels = 50 µm, insets = 10 µm.