Gall bladder volumes (mean (SEM)) in the fasting state, during, and after modified sham feeding (MSF) and in response to cholecystokinin (CCK) infusion in controls (open triangles) and patients with slow transit constipation (STC; closed triangles). Gall bladder volumes (mean (SEM)) in the fasting state, during, and after modified sham feeding (MSF) and in response to cholecystokinin (CCK) infusion in controls (open triangles) and patients with slow transit constipation (STC; closed triangles). C Penning et al. Gut 1999;45:264-268 Copyright © BMJ Publishing Group Ltd & British Society of Gastroenterology. All rights reserved.