Thioredoxin and thioredoxin reductase show function-related changes in the gastric mucosa: immunohistochemical evidence.

Low levels of thioredoxin and thioredoxin reductase immunoreactivity were demonstrated immunohistochemically in rat gastric epithelial cells. The intensity was influenced by feeding and fasting, the former resulting in diminished reactions. Acute vagotomy, which abolishes basal acid secretion, resulted in a strongly increased thioredoxin immunoreactivity in all gastric epithelial cells. Stimulation of vagotomized rats with pentagastrin and carbachol reduced the levels of thioredoxin and thioredoxin reductase. Atropine and omeprazole (in stimulated, vagotomized rats) completely inhibited acid secretion, but caused different effects on the thioredoxin levels of gastric cells. Atropine restored the thioredoxin immunoreactivity in most gastric epithelial cells to that of the unstimulated, vagotomized controls. Omeprazole, however, did not reverse the effects of stimulation, and, except in the parietal cells, weaker fluorescence was observed. Similar reaction patterns were seen for thioredoxin reductase, although at lower staining intensities. The results demonstrate that thioredoxin and thioredoxin reductase are expressed in resting cells, and to a lower extent in cells with ongoing secretion.