Glucocorticoids have many effects in the stomach. It is well known that glucocorticoids function via the glucocorticoid receptor (GR). In this study, GR immunoreactivity in the gastric mucosa of normal and adrenalectomized (ADX) rats was examined immunohistochemically by using specific polyclonal antibodies against rat GR. In the gastric mucosa of normal rats, GR immunoreactivity was observed in the nuclei of morphologically identified parietal cells. Double immunohistochemical staining for GR and parietal cell, anti-parietal cell antibody-positive cells also had positive immunoreactions for GR. In the gastric mucosa of ADX rats, GR immunoreactivity was diminished in the nuclei of parietal cells but weak immunoreactivity was still observed. These results suggest that parietal cells in the gastric mucosa of rats are directly regulated by glucocorticoids via its receptors. Nuclear GR immunoreactivity in gastric parietal cells is thought to depend on the circulating ligands.