Objectives: Erythromycin, a motilin-like agent, stimulates gallbladder contraction in healthy control subjects. Because the action of erythromycin is cholinergic dependent and possibly related to premature phase III migrating motor complex activity in the antrum, we investigated the effect of erythromycin on gallbladder volume in six patients with truncal vagotomy without gastric resection and 14 patients with antrectomy (6 with Billroth I anastomosis, 8 with Billroth II anastomosis), and we compared the results obtained with those in eight healthy controls. In addition, the effect of meal ingestion on gallbladder volume was studied.
Methods: Gallbladder volumes, measured with ultrasonography, were determined every 15 min for 180 min after erythromycin infusion (3 mg/kg i.v.), as well as 30 and 60 min after meal ingestion.
Results: Basal gallbladder volumes were not significantly different among the four groups. Erythromycin induced a significant (p < 0.01-0.05) gallbladder contraction of maximal 46 +/- 6% in the controls, 49 +/- 9% in the patients with truncal vagotomy, and 38 +/- 7% in the patients with antrectomy and Billroth I anastomosis. In the patients with antrectomy and Billroth II anastomosis, no significant reduction in gallbladder volume after erythromycin was observed. Meal-induced gallbladder contraction was normal in all patients, including those with Billroth II anastomosis.
Conclusions: These results indicate that neither the long vagus nerve nor the antrum is essential for erythromycin-induced effects on the gallbladder. Because no significant reduction in gallbladder volume in response to erythromycin was observed in the patients with antrectomy and Billroth II anastomosis, we suggest that duodenojejunal anatomical integrity is essential for erythromycin-induced gallbladder contraction.