Neural and hormonal peptides in rectal biopsy specimens from patients with Chagas' disease and chronic autonomic failure.

The neural and hormonal peptide content of rectal biopsy specimens from 10 patients with chronic autonomic failure, 10 patients with chronic gastrointestinal Chagas' disease, and 13 controls was studied with radioimmunoassay and immunocytochemistry. In the patients with Chagas' disease the mean concentrations of rectal vasoactive intestinal polypeptide, enteroglucagon, substance P, and somatostatin were all less than half of those in controls and in patients with chronic autonomic failure. Immunocytochemistry revealed a considerable reduction in the number and immunostaining of the peptide-containing cells and nerves. Concentrations of regulatory peptides in the rectum are thus reduced in association with intrinsic but not extrinsic autonomic neuropathy.