Brain Peptides Secreted by Gut Tumors

To the Editor: Several peptides are neurotransmitter candidates in the brain and are also localized to the gastrointestinal tract and associated organs such as the pancreas. Circulating levels of each of these peptides elicit characteristic vascular and autonomic effects. For example, tumors secreting somatostatin are associated with hyperglycemia, hypoinsulinemia and hyperglucagonemia.^1,2 We are writing to suggest that other hitherto undescribed peptide-secreting tumors might be identified on the basis of their physiologic effects. Neurotensin, a 13-amino acid peptide, is localized to neurons in the brain and to apparently secretory cells in the small intestine. Parenterally injected neurotensin produces hyperglycemia, with hyperglucagonemia. No extract is available for articles shorter than 400 words.