Prokinetic Effect of Duodenal Extract on Ovine Gallbladders

Abstract

Objective: It is known that the macrolide antibiotic erythromycin stimulates gastrointestinal and gallbladder motility by an as yet unidentified mechanism. It was the objective of this study to investigate the mechanism of the gallbladder motility-stimulating effect of erythromycin. Methods: In our experiments we used strips of sheep gallbladders measuring isometric tension in organ baths. Since erythromycin itself did not induce contraction we examined the prokinetic effects of sheep duodenal extract, incubated with (DEX) or without (blank) erythromycin (10^–5 M). Results: Both DEX and blank elicited gallbladder contraction associated with heat-stable, water-soluble but not with lipid-soluble duodenal prokinetic factor. The factor is unrelated to motilin or cholecystokinin and is only partially (<20%) blocked by atropine (10^–6 M) and not affected by the pretreatment with dexamethasone or somatostatin. Conclusion: It was concluded that erythromycin indirectly stimulates contraction of ovine gallbladders through the endogenous release of a duodenal prokinetic factor.