There has been considerable debate about the ontological origin of gut endocrine cells as being either from the neural crest (or primitive epiblast) or from the endodermal stem cell. We have attempted to define the ontological origin of endocrine cells by applying an experimental system that uses a marker to identify one of the two phenotypes present in chimaeric mice as suggested by Ponder et al. (1985). This study involved two separate experiments. The first made use of the unique staining

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... perties of Dolichos biflorus agglutinin (DBA), a lectin that binds to the N-acetyl galactosamine sugar residues present on the surface of C57Bl mouse gut, but absent from RoRIII mouse gut, in C57Bl----RoIII mouse chimaeras at the ultrastructural level. A four-stage procedure for staining at the EM level was developed. Although mature villous endocrine cells stained for DBA, immature endocrine cells did not, either in the positive crypts of chimaeric mouse gut or in gut from C57Bl positive controls. Thus a second marker was chosen. This experiment combined immunocytochemistry (to identify gastric antral gastrin cells chosen as a representative neuroendocrine cell) with in situ DNA hybridization for the mouse male chromosome repeat sequence PY 353 (to identify XY cells) in XX----XY chimaeric mice. This study showed that the sex chromosomal pattern in the gastrin cells parallels that of other cells in the same gastric gland and therefore are clonal with them. This suggests that gut endocrine cells share a common stem cell with other epithelial cell lineages in the antrum and are endodermally derived.