APUD-like cells in the primitive gut of a 27 day old human embryo

A 27 +/- 1 days old human embryo arising from an ectopic pregnancy was incubated with 3,4, L-dihydroxyphenylalanine (L-DOPA) to investigate whether cells of the gut primordium have at this early stage of development, the ability to take up the amine precursors. We could observe that a few cells exhibiting greenish fluorescence were located in the epithelium wall of the fore gut. Most of them were situated in contact with the basal lamina and possessed a long apical process extending over towards the gut lumen. The uptake of amine precursor, the morphology and the location of these cells strongly suggest that they represent the gut endocrine precursor cells of the human embryo.