Comparison of methylated prostaglandin E2 analogues given orally in the inhibition of gastric responses to pentagastrin and peptone meal in man.

In 32 healthy male volunteers the effects on gastric secretion of three methyl analogues of prostaglandin (PG) E2 have been studied, namel, 15 (R) -15-methyl PGE2 methyl ester, 15 (S) -15-methyl PGE2 methyl ester, and 16, 16-dimethyl PGE2. Secretion was measured for 30 min and a PG analogue at doses ranging from 1.25 to 2.5 mug per kg or a placebo was administered. Gastric secretion was then stimulated either by an intravenous infusion of pentagastrin (2 mug per kg-hr) or by a peptone meal with acid secretion determined by intragastric titration technique. The tests were randomized and double blind. All three methyl PG analogues exhibited a profound and prolonged inhibitory action on gastric acid and pepsin secretion induced by pentagastrin. PG analogues caused almost complete inhibition of gastric acid response to a peptone meal accompanied by a significant reduction in the serum concentration of immunoassayable gastrin. Except with the highest dose of PG (S) -15-methyl PGE2 methyl ester, which caused abdominal discomfort and single episodes of diarrhea in some subjects, no symptoms or untoward biochemical effects were observed. It is concluded that these methylated PG analogues are very potent inhibitors of gastric acid and pepsin secretion stimulated by pentagastrin or a meal and may have clinical potential in the treatment of peptic ulcer.