LHRH antagonist inhibits gastric cell proliferation in suckling rats

The cell proliferation of the gastric epithelium is stimulated by food depr ivation in suckling rats, and LHRH inhibits this process as it does in othe r hyperproliferating tissues. However, as LHRH antagonist is also being use d as a potent antiproliferative agent for tumors, this study aims to invest igate whether it plays any role on the cell proliferation of the gastric ep ithelium. Seventeen-day-old rats were fasted for 20 h and treated with LHRH antagonist, LHRH, or both during this period. The following morning, anima ls were injected with BrDU to label proliferating cells, and were sacrifice d 1 h later. Paraffin sections of the gastric mucosa were processed for imm unohistochemistry and BrDU labeled and non-labeled epithelial cells were co unted 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 inhibi tory role on the hyperproliferating gastric epithelium. These results sugge st that both LHRH agonist and antagonist can influence the proliferative ac tivity in suckling rats, though the mode of action remains to be determined . (C) 1999 Elsevier Science B.V. All rights reserved.