Formaldehyde-ozone-induced fluorescence in isolated gastrin granules

Fluorescence histochemical methods for the study of peptide hormone-producing cells

Fluorescence histochemical methods for the demonstration of specific residues in peptides and proteins are reviewed: Formaldehyde-ozone for NH2-terminal tryptophan, formaldehyde-HCl for tryptophan regardless of position in the peptide, OPT for NH2-terminal histidine, formaldehyde-fluorescamine for "protected" amino groups, nitroso-naphthol for tyrosine, and phenanthrenequinone for arginine residues. The methods are potent in demonstrating granule-stored material in peptide hormone-producing cells. Also quinacrine, the fluorescent anti-malaria agent, binds to granular components, as yet unidentified, in several endocrine cell types. In many cases the fluorescence histochemical methods seem to demonstrate peptides and proteins distinct from the known hormones.

Endocrine pancreatic tumors

The pathology and cell biology of endocrine pancreatic tumors are reviewed. It is probable that all these tumors are "functioning" in the sense that they elaborate hormones that cause more or less conspicuous clinical syndromes. Identification of such secretory products is essential for an optimal diagnosis, localization, treatment, and follow-up. Recent data indicate that endocrine pancreatic tumors evolve from progenitor cells of ducts. This histogenetic mechanism may explain the occurrence not only of mixed or multihormonal tumors but also of tumors producing hormones that are absent from the adult human pancreas. In addition to their clinically apparent effects, many endocrine pancreatic tumors affect the surrounding endocrine pancreas in a characteristic way. The mechanisms behind and the potential diagnostic usefulness of these changes are discussed.