Fat Inhibits Meal-Stimulated Gastric Acid Secretion after Prostaglandin Synthesis Inhibition by Indomethacin in Man

Abstract

The effect of cyclooxygenase inhibition by indomethacin on the mechanism by which fat inhibits gastric acid secretion was studied in eight healthy men. Oral 200-mg doses of indomethacin administered 15 h and 2 h before testing is known to inhibit prostaglandin synthesis by 90%, as determined by prostaglandin E₂ generation assay on endoscopically obtained gastric mucosal biopsy specimens. Fat-induced inhibition of gastric acid secretion was evaluated by intragastric administration of 200 ml vegetable oil or glucose (control) for 30 min, followed by intragastric titration with peptone at pH5.5 for 2h. The mean acid output was significantly lower after fat (8 ± 0.2 mmol 30 min¹) as compared with control (12 ± 0.5 mmol 30 min⁻¹). The fat-induced inhibition was unaffected by indomethacin treatment, and the plasma gastrin responses were similar in all groups. It is concluded that the participation of cyclooxygenase products such as prostaglandins in the mechanisms by which fat inhibits the gastric phase of acid secretion in man is likely to be minor.

Key Words:

• Acid secretion
• fat
• gastric emptying
• gastrin
• human
• indomethacin
• prostaglandins