Abstract
Numerous peptides (neuropeptides) have been recently found to be present in both the nervous and endocrine systems composing what is now known as the diffuse neuroendocrine system. Two immunological methods, radioimmunoassay and immunocytochemistry, have been used here in combination to study their distribution and cellular localization. A number of these neuropeptides have recently been found to be abnormal in disease state, thus providing further information as to their role in normal and pathological conditions.