Previous studies in animals and humans demonstrated that
nocloprost, a stable
prostaglandin E2 analogue, shows very high gastroprotective potency, relatively weak gastric inhibitory activity, and low systemic bioavailability after
oral administration. In this study the effects of
nocloprost on gastric acid secretion and intraluminal pH and on gastric emptying and plasma
gastrin levels were determined in humans.
Nocloprost at doses of 50 and 100 micrograms was ineffective, but at a dose of 200 micrograms it reduced the response to
pentagastrin significantly and that to a
peptone meal by 30-50% and abolished plasma
gastrin response without affecting the rate of gastric emptying.
Nocloprost given at a dose of 100 micrograms three times daily 30 min before the major meals (breakfast, lunch, and dinner) did not affect intragastric pH significantly as monitored by continuous intraluminal pH-metry. We conclude that
nocloprost does not affect gastric acid secretion or intraluminal pH when applied at a dose (50-100 micrograms) that is gastroprotective and that is proposed for
peptic ulcer therapy. A higher dose (200 micrograms) of
nocloprost causes moderate gastric acid inhibition and suppression of plasma
gastrin release without affecting gastric emptying or causing any side effects.