Selenium-dependent glutathione peroxidase-GI is localized in basal granulated cells of rat stomach

Abstract

In this study, we prepared, using a synthetic peptide as the immunogen, a polyclonal antibody against gastrointestinal glutathione peroxidase (GPx-GI), a recently discovered selenium-dependent GPx isozyme, and the occurrence and distribution of GPx-GI immunoreactivity was examined in the rat gastric mucosa. The antibody was shown by western blotting to recognize a 24 kDa GPx-GI protein from the gastric adenocarcinoma cell line, which expressed GPx-GI mRNA. During an immunoprecipitation analysis using a 75Se-labeled cell lysate, the antibody against GPx-GI did not cross-react with other GPx isozymes such as cytosolic GPx or phospholipid hydroperoxide GPx. This antibody reacted with the 24 kDa protein of the rat stomach extracts. Immunohistochemical analysis of the rat gastric mucosa revealed that GPx-GI immunoreactivity actually existed in certain basal granulated cells, which were confirmed by the anti-PGP 9.5 antibody. These results suggest that the GPx-GI antibody may be a very useful tool for further clarification of the tissue-specific functions of GPx-GI.