Gastrointestinal hormones and apudomas
Interest and developments in gastrointestinal hormones “exploded” since gastrin was isolated by Gregory et al1 in 1964. Progress in radioimmunoassay and chromatography had been responsible for the “unleashing” of peptides whose nomenclature and properties are scarcely defined before newer peptides are identified and reported. It sometimes seems that there are more peptides than chemical effects attributed to them.
Coupled with advances in the chemistry of peptides has been their identification in several clinical syndromes. These syndromes are now more easily recognized than previously because of increasing awareness and the availability of specific therapy (e.g., cimetidine for Zollinger-Ellison syndrome).
Basic information about these hormones has been summarized in three recent reviews.2–4 In this paper, the three identified hormones (gastrin, secretin, and cholecystokinin-pancreozymin) are discussed, and also several of the candidate hormones (peptides that await further clarification before classification as hormones), their sites of origin, mechanism of action, and relation to clinical syndromes.Cells of origin
Many peptides and hormones may share a common cell of origin. This concept was popularized by Pearse et al5, 6 who noted the structural and chemical similarities of these cells. Anatomically, the cells are similar to ganglion cells of the neural crest. These cells also share chemical similarities (demonstrated by histochemical techniques). Five of these properties are high fluorogenic amine content, amine precursor uptake, amino acid decarboxylase, side-chain carboxyl groups, and specific immunochemical properties. These common characteristics have led to the acronym APUD cells for amine precursor uptake and decarboxylase cells. The current list of these . . .