Alteration of gastrin-producing cells in rat antral mucosa after truncal vagotomy.

Gastrin-producing cells (G cells) were studied in the rat antral mucosa after truncal vagotomy. Significant elevation of circulating gastrin levels was observed from 12 hours after the operation and this was sustained throughout the entire experimental period. Upon light microscopic observation, G cells showing positive immunostaining for G17 were significantly increased in number at 2 days, 1, 2 and 3 weeks after the operation and were a more prominent cell type than G cells containing positive reaction product for G34 throughout the entire experimental period. Ultrastructural changes occurred predominantly in G cells, which showed hypertrophy of Golgi complexes and noticeable increases in the amounts of rough endoplasmic reticulum between 2 days and 3 months after the operation. During these periods, secretory granules apparently increased in number and displayed various degrees of electron density. Immature, highly electron-dense granules appearing in or near the Golgi stacks mainly showed localization of immuno-gold particles for G34, whereas mature granules with low electron-density predominantly demonstrated a positive reaction product for G17. The Golgi apparatus and rough endoplasmic reticulum were free of any immunoreaction for either G34 or G17.