Effect of estradiol treatment on the secretion and structure of gastric H⁺ and pepsin-secreting cells in the rat

Abstract

Gastrin-stimulated secretory rate of gastric H+ and pepsin were markedly inhibited (P < 0.001) in ovariectomized rat after 7 days of estradiol treatment (80 μg/kg/day) in comparison to ovariectomized untreated rat and sham control. In correlation to the secretions, the majority of parietal cells failed to show the typical ultrastructural transformation associated with active secretion. Pyknotic nuclei with dilatation of nuclear envelope and degenerative changes were observed in the parietal cells. Meanwhile, the chief cell showed inactive characteristics in that a large number of pepsinogen granules were retained in the cells. In contrast, in ovariectomized untreated rat, the rate of gastrin-stimulated H+ and papsin secretion were not significantly different from the sham (P > 0.05). Consistent with secretion, after gastrin stimulation, the morphology and ultrastructure of the parietal cell and chief cell showed active secretory features in a pattern similar to changes observed in sham. The results suggest that impairment in the structure of the functional parts of secretory cells by estrogen treatment was a factor contributing to the inhibition of the gastric secretions.