Misoprostol induces gallbladder contraction during fasting, but does not influence postprandial emptying : an ultrasound study in healthy subjects

Objective : The aim of this study was to evaluate the effect of the PGE1 analogue, Misoprostol, on gallbladder fasting volume and meal-stimulated emptying. Prostaglandins' effects on the gallblad- der were studied principally regarding mucus production during lithogenesis. In the few in vitro and in vivo studies, contradictory results concerning their influence upon gallbladder motility were obtained. Subjects : 13 healthy subjects, 8 females, 5 males, aged 23.4 years (ranges 22-25). Methods : Gallbladder volumes were assessed by ultrasound, after measuring the three diameters of the gallbladder in two per- pendicular planes, using a conventional 2D equipment and a 3D equipment, after the 3D-reconstruction of the gallbladder. The volumes were calculated by means of the ellipsoid formula. Gallbladder emptying variables (residual volume, ejection frac- tion, area under emptying curve) were assessed during 90 minutes after a test meal (14 g fat, 425 kcal). Gallbladder emptying was evaluated in each subject on three different days : without prior Misoprostol administration, after 200 mg Misoprostol, and after 400 mg Misoprostol. Misoprostol was given orally as a single dose, 60 minutes before the meal. The two-tailed Student's t test for paired observations was used to compare the results. Results : Misoprostol induced a significant decrease of the gall- bladder fasting volume : from 12.8 ± 4.4 (SD) ml (controls) to 9.1 ± 3.6 ml (200 mg Misoprostol) and 5.4 ± 2.6 ml (400 mg Misoprostol). Gallbladder meal-stimulated emptying was not influenced by Misoprostol. Conclusions : Our results indicated that, in healthy subjects, misoprostol induced a dose-dependent gallbladder emptying in the fasting state, but did not influence gallbladder postprandial emp- tying. Pre-prandial Misoprostol administration might be useful to treat gallbladder stasis in patients with chronic constipation, thus preventing gallstone formation. (Acta gastroenterol. belg., 2002, 65, 191-195).