Abstract
Assay of regulatory peptides has an established role in the diagnosis and management of several peptide-producing tumours, including endocrine pancreatic tumours, carcinoid tumours, medullary thyroidea carcinomas, pheochromocytomas, and neuroblastomas. Proper sample handling (rapid cooling and freezing) is important since most regulatory peptides (except gastrin and pancreatic polypeptide) are labile in plasma. The immunoassay should preferably have broad specificity for the peptide family to be analysed since endocrine tumours may result in elevated concentrations of different spectra of the peptides in individual patients. From the analytical point of view, this is in contrast with the preferences of the physiologist who is usually interested in measuring the concentration of a single member of the peptide family with as high specificity as possible.