CELLULAR-DISTRIBUTION OF PROLACTIN RECEPTORS IN HUMAN DIGESTIVE TISSUES

In the present study we analyzed the expression of prolactin receptors (PRLR) in human digestive tissues by immunohistochemistry. PRLR immun oreactivity was primarily localized in the cytoplasm. However, in some organs (liver and salivary glands) a nuclear positivity was also foun d. The liver was used as control and showed a diffuse immunostaining i n the parenchymal cells. In the gastrointestinal tract, PRLR immunorea ctivity was observed in the mucosa, muscularis layer, and nervous plex uses. The more intense immunostaining in the mucosa of the different s egments was as follows: esophagus, superficial layers of the stratifie d squamous epithelium and mucous glands; stomach, parietal cells; smal l intestine, absorptive and Paneth cells; and colon, surface epitheliu m and superficial half of the crypts of Lieberkuhn. In the salivary gl ands, immunoreactivity was strong in the mucous tubules, moderate in t he ducts, and weak in the serous cells. Endocrine pancreas showed a mo re intense immunoreactivity than the pancreatic acini. By serial secti ons of the islets of Langerhans we showed that immunostaining was conf ined to B cells. These findings demonstrate the widespread distributio n of PRLR in human digestive tissues and its localization both in cyto plasms and nuclei.