The APUD concept was proposed in 1966 by Pearse and his collaborators in London and is the short form for Amine (and amine precursor) precursor uptake and decarboxylation.   These investigators noted that a group of cells which exhibited similar cytochemical characteristics were found scattered all over the body and that all the cells can take up amines and decarboxylate them.   Aside from this, they are all also polypeptide producing cells.   When these cells become neoplastic (develop tumor)  their neoplasia seem also to affect more than one cell type simultaneously e.g. as in multiple endocrine adenopathies, APUD cells are also members of the diffuse neuroendocrine system of Pearse (DNES). and are mostly recognised today as argentaffin cells.

            Amongst the group of cells are the thyroid C cells which produce calcitonin, islet of Langerhans cell (α and ), pituitary gonadotrophs and some scattered argentaffin cells of the gastrointestinal tract (see Table below).

            The characteristics of APUD cells are as follows:

  1. Fluoregenic amine content e.g. 5-hydroxytrytamine or catecholamine,

  2. Amine precursor uptake e.g. DOPA

  3. Amino acid decarboxylase

  4. α-glycerophosphate dehydrogenase

  5. Non-specific esterases

  6. Specific endocrine granule ultrastructure

  7. Immunofluorescence and immune electron cytochemistry susceptibility.

  8. Argyrophilia

  9. Some cells have argentaffin reaction

  10. Some cells are alcianophilic

  11. Masked metachromasia to toluidine blue

  12. Lead hematoxylin stain

APUD cells  


Check diffuse neuroendocrine system (DNES)

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  Electronic School of Medicine 
Creator: Oluwole Ogunranti


Closed APUD cell electron micrograph with basal secretion


Cell types

Organ integration



Chemical Pathology