LHRH antagonist inhibits gastric cell proliferation in suckling rats

The cell proliferation of the gastric epithelium is stimulated by food deprivation in suckling rats, and LHRH inhibits this process as it does in other hyperproliferating tissues. However, as LHRH antagonist is also being used as a potent antiproliferative agent for tumors, this study aims to investigate whether it plays any role on the cell proliferation of the gastric epithelium. Seventeen-day-old rats were fasted for 20 h and treated with LHRH antagonist, LHRH, or both during this period. The following morning, animals were injected with BrDU to label proliferating cells, and were sacrificed 1 h later. Paraffin sections of the gastric mucosa were processed for immunohistochemistry and BrDU labeled and non-labeled epithelial cells were counted to determine the labeling index (LI). None of the hormone treatments changed body weight or the morphology of the stomach. Apoptotic cells were observed in the gastric gland in treated rats. The LI were inhibited by the antagonist, LHRH or both, showing that the LHRH antagonist plays an inhibitory role on the hyperproliferating gastric epithelium. These results suggest that both LHRH agonist and antagonist can influence the proliferative activity in suckling rats, though the mode of action remains to be determined.