[Immunohistochemical localization of pituitary peptides in the rat pyloric antrum mucosa]

Several peptides normally produced in the anterior pituitary lobe were searched in rat antral mucosa by immunocytochemistry. Peptides derived from pro-opiomelanocortin were tested: some endocrine cells were immunoreactive with ACTH 17-39 antiserum, and only a few elements were stained with ACTH 1-24 and beta LPH antisera. No immunoreactive cells were observed using alpha MSH, beta MSH and beta endorphine antisera. Using an antiserum against beta endorphin, a few cells and nerve fibres were immunostained. The other pituitary hormones were also tested: numerous antral cells contained immunoreactive GH, and some cells immunoreactive PRL or compounds chemically related to these hormones. No cells were stained with antisera directed against glycoproteic hormones. This work showed that several peptides previously localized in the pituitary gland were found in the antral mucosa. Further studies are needed to identify the cell types containing these peptides and to determine their origin.