Effect of Short- and Long-Term Feeding of Omeprazole on Rat Gastric Endocrine Cells

Abstract

Rats were tube-fed with omeprazole (40 μmol/kg body weight twice daily) for 30 and 60 days. As a result, fasting plasma gastrin levels were significantly elevated, while plasma somatostatin levels remained normal. Gastrin concentrations in the antral mucosa were unchanged after 30 days, but significantly elevated after 60 days. The relative stomach weight and the area of the antral and oxyntic mucosa increased significantly; however, the oxyntic mucosa thickness and the volume density of the parietal cells did not increase. Highly significant changes occurred in the endocrine cells of the antrum and corpus. The volume density of the argyrophilic (Grimelius technique) cells of the oxyntic mucosa increased time-dependently, and so did the volume density of the antral G cells, while the volume density of the antral D cells decreased. This resulted in a remarkable increase in the G/D cell ratio. All functional and morphological changes are reversed 42 days after omeprazole feeding for 60 days. The findings in the endocrine cells of the antral mucosa are explained by the omeprazole-induced permanent elevation of the intragastric pH and in the endocrine cells of the oxyntic mucosa by the following hypergastrinaemia.

Action of somatostatin analogue (SMS 201–995) on the growth‐promoting effect resulting from sustained achlorhydria in rat gastric mucosa, with special reference to endocrine cell behaviour

“…The increase in antral mucosal height was observed after only 1 month of treatment (+480/0) but was not significant (P=O-lO, n = 4), while at that time no evident increase in fundic mucosal height was noted between control and Om groups (data not shown). This is in keeping with previous published results [22] but is at variance with others 1171. It is well known that gastrin exerts a trophic effect on fundic mucosa [24-261, however discrepancies exist concerning its action on antral mucosa [9, 24,27].…”

The Achlorhydria-Carcinoid Sequence: Role of Gastrin

“…Here the volume density increased from 0.73 ± 0.1 to 0.86 ± 0.09. This increase was not significant and is much smaller than that observed in rats after 8 weeks of treatment with 14 mg/kg omepra zole daily [ 16], and were far below the values estimated in 8 patients with gastrinoma (1.37 ± 0.22%). No clusters of endocrine cells were found.…”

Abnormal functional and morphological regulation of the gastric mucosa in histamine H2 receptor–deficient mice

“…Chronic application of acidinhibitory drugs elevates serum gastrin levels (14,16,30), and it has been suggested that the gastric pH influences the population of endocrine cells such as gastrinproducing G cells (30)(31)(32). The long-term elevation of gastric pH may increase G-cell density and then elevate serum gastrin levels.…”