Localization of luteinizing-hormone releasing hormone binding sites in thegastric mucosa of suckling rats

Luteinizing-hormone releasing hormone (LHRH) is a hypothalamic and milk-bor ne hormone that inhibits the cell proliferation of gastric epithelium in de veloping rats, although the mechanism of such action is unknown. We investi gated the presence of binding sites for LHRH in the stomach of suckling rat s after the injection of the hormone. Immunofluorescence at the confocal mi croscopy level revealed that LHRH binds to gastric cells, being particularl y abundant over the gland. Different fluorescent lectins were used to ident ify gastric cell types and determine which were labeled by the hormone. Col ocalization studies in these double-labeling experiments showed that LHRH s taining colocalizes with parietal cells, suggesting the presence of binding sites in these cells. The three-dimensional (3-D) reconstruction of isolat ed parietal cells revealed the localization of the signal, which appears to be in the membrane of the canalicular region. These results suggest that t here are binding sites for LHRH in the gastric epithelium, specifically in parietal cells, and they might play a role in the control of cell prolifera tion during suckling. Anat Rec 264:43-50, 2001. (C) 2001 Wiley-Liss, Inc.