Does the nutrient drink test accurately predict postprandial gastric volume in health and community dyspepsia?

Nutrient drink tests have been proposed as a surrogate for measurement of gastric accommodation. To study the relationship of maximum tolerated volume (MTV) during nutrient drink test and gastric volumes measured by single-photon emission computed tomography (SPECT) in healthy controls and functional dyspepsia (FD) patients. We reviewed data from 85 healthy controls and 35 FD residents of south-eastern Minnesota. All underwent standardized nutrient drink and SPECT studies between August 2000 and June 2003. To test for associations between nutrient drink test and SPECT gastric volumes, we used multiple linear regression and partial regression analyses, assigning age, gender, dyspepsia status and postprandial symptoms as covariates in the model. In the combined group (healthy and FD), MTV was weakly associated with fasting gastric volume (r = 0.43, P = 0.0001) and with volume response to feeding (r = 0.25, P = 0.006). In the FD group, associations were similar (fasting r = 0.53, P = 0.001; postmeal r = 0.32, P = 0.06). After accounting for covariates, MTV only explained 13 and 3% of variations in fasting and postprandial volumes measured by SPECT. MTV during the nutrient drink test does not accurately reflect gastric volume measurements by SPECT in healthy controls and a sample of people in the community with FD.

Effect of cyclooxygenase-2 inhibitors on gastric emptying and small intestinal transit in humans.

Endogenous prostaglandins regulate smooth muscle activity; prostaglandins and cyclooxygenase (COX) inhibitors influence gastrointestinal motility in inflammatory states such as postoperative ileus in animal models. The objective of this study was to evaluate the effects of two COX-2 inhibitors on gastric emptying and intestinal transit in healthy humans. In a double-blind, placebo-controlled, parallel-group study, 66 healthy volunteers were randomized to one of two commercially available oral COX-2 inhibitors (celecoxib and rofecoxib), cisapride (positive control), or placebo. Following 7 days on therapy, study participants underwent a test of gastric emptying and small bowel transit of liquids and solids using scintigraphy. Data were analysed using Kruskal-Wallis (ANOVA on ranks)and Mann-Whitney rank sum tests. There were significant group effects on transit of solids: gastric emptying (ANOVA, P = 0.005) and small bowel transit (ANOVA, P = 0.056). However, neither COX-2 inhibitor significantly accelerated the liquid or solid gastric emptying or small bowel transit compared with placebo. The positive control, cisapride, accelerated gastric emptying of solids (post-lag slope of gastric emptying, P < 0.05), and small bowel transit of solids (t10%, P = 0.016). At maximum clinically approved dosages, celecoxib and rofecoxib have no significant effects on gastric emptying or small intestinal transit in healthy humans. Cisapride accelerates gastric emptying and small bowel transit in healthy humans.

Effects of glucagon-like peptide-1 and feeding on gastric volumes in diabetes mellitus with cardio-vagal dysfunction.

Glucagon-like peptide-1 (GLP-1) increases gastric volume in humans possibly through the vagus nerve. Gastric volume response to feeding is preserved after vagal denervation in animals. We evaluated gastric volume responses to GLP-1 and placebo in seven diabetic patients with vagal neuropathy in a crossover study. We also compared gastric volume response to feeding in diabetes with that in healthy controls. We measured gastric volume using SPECT imaging. Data are median (interquartile range). In diabetic patients, GLP-1 did not increase gastric volume during fasting [5 mL (-3; 30)] relative to placebo [4 mL (-14; 50) P = 0.5], or postprandially [Delta postprandial minus fasting volume 469 mL (383; 563) with GLP-1 and 452 mL (400; 493) with placebo P = 0.3]. Change in gastric volume over fasting in diabetic patients on placebo was comparable to that of healthy controls [452 mL (400; 493)], P = 0.5. In contrast to effects in health, GLP-1 did not increase gastric volume in diabetics with vagal neuropathy, suggesting GLP-1's effects on stomach volume are vagally mediated. Normal gastric volume response to feeding in diabetics with vagal neuropathy suggests that other mechanisms compensate for vagal denervation.

A randomized controlled trial of a probiotic, VSL#3, on gut transit and symptoms in diarrhoea-predominant irritable bowel syndrome.

AIM: To investigate the effects of a probiotic formulation, VSL#3, on gastrointestinal transit and symptoms of patients with Rome II irritable bowel syndrome with predominant diarrhoea. METHODS: Twenty-five patients with diarrhoea-predominant irritable bowel syndrome were randomly assigned to receive VSL#3 powder (450 billion lyophilized bacteria/day) or matching placebo twice daily for 8 weeks after a 2-week run-in period. Pre- and post-treatment gastrointestinal transit measurements were performed in all patients. Patients recorded their bowel function and symptoms daily in a diary during the 10-week study, which was powered to detect a 50% change in the primary colonic transit end-point. RESULTS: There were no significant differences in mean gastrointestinal transit measurements, bowel function scores or satisfactory global symptom relief between the two treatment groups, pre- or post-therapy. Differences in abdominal bloating scores between treatments were borderline significant (P = 0.09, analysis of covariance). Further analysis revealed that abdominal bloating was reduced (P = 0.046) with VSL#3 [mean post- minus pre-treatment score, - 13.7; 95% confidence interval (CI), - 2.5 to - 24.9], but not with placebo (P = 0.54) (mean post- minus pre-treatment score, - 1.7; 95% CI, 7.1 to - 10.4). With the exception of changes in abdominal bloating, VSL#3 had no effect on other individual symptoms: abdominal pain, gas and urgency. All patients tolerated VSL#3 well. CONCLUSION: VSL#3 appears to be promising in the relief of abdominal bloating in patients with diarrhoea-predominant irritable bowel syndrome. This is unrelated to an alteration in gastrointestinal or colonic transit.

SPECT imaging of the stomach: comparison with barostat, and effects of sex, age, body mass index, and fundoplication. Single photon emission computed tomography.

BACKGROUND: Impaired gastric accommodation may lead to dyspeptic symptoms. A non-invasive method using single photon emission computed tomography (SPECT) has been developed to measure gastric volumes. AIMS AND METHODS: Our aims were: to assess the accuracy of SPECT with three dimensional image analysis to measure balloon volumes in vitro; to compare gastric barostat balloon volumes measured post-meal and post-distension with total gastric volumes measured simultaneously with SPECT; to present normal gastric volume data for healthy adults; and to compare SPECT data in health with symptomatic post-fundoplication patients. RESULTS: In vitro balloon volumes measured by SPECT were highly accurate (R(2)=0.99). When measured simultaneously by gastric barostat and SPECT, postprandial/fasting volume ratios (2.2 (0.12) (mean (SEM)) v 2.3 (0.15), respectively; p=0.6) and post-distension volume ratios (1.4 (0.1) v1.3 (0.1); p=0.2) were highly comparable. In females, postprandial gastric volumes (675 (14) v 744 (20) ml for males; p=0.004) and changes in gastric volumes (464 (14) ml v 521 (20) ml for males; p=0.01) measured by SPECT were significantly lower than in males. No effects of age or body mass index were noted. The postprandial/fasting gastric volume ratio by SPECT was lower in post-fundoplication patients (2.7 (0.2)) than in healthy controls (3.4 (0.1); p=0.003). CONCLUSIONS: SPECT provides a non-invasive estimate of the effect of a meal on total gastric volume that is comparable to changes in balloon volume observed with the gastric barostat. The SPECT technique is promising for investigation of gastric volumes in health and disease and the effects of pharmacological agents.

Model of rapid gastrointestinal transit in dogs: effects of muscarinic antagonists and a nitric oxide synthase inhibitor.

Our aims were to establish a canine model of rapid gastrointestinal transit, and to test the effects of muscarinic receptor antagonists (atropine, pirenzepine, AF-DX116, and darifenacin), and an NOS inhibitor, L-nitro-N-arginine (L-NNA) in this model. For gastric emptying and small bowel transit, 99mTc-labelled DTPA were added to a meal of skimmed milk (236 mL) that contained 2.4 g of magnesium hydroxide. Regional colonic transit was measured by111In-labelled beads placed in a capsule that released isotope in the proximal colon. Scintiscans were taken at regular intervals and indices of transit were calculated. Drugs were administrated intravenously. Gastric emptying, small bowel and colonic transit were rapid. Atropine and darifenacin (a selective M3 antagonist) delayed gastric emptying and colonic transit, the selective M1 and M2 muscarinic antagonists did not. The muscarinic blockers did not slow small bowel transit. L-NNA delayed small bowel and colonic transit but did not slow gastric emptying. A model suitable for the preclinical study of antidiarrhoeals was established. M3 receptors are important in the control of gastric emptying and colonic transit, and NOS inhibition slowed small bowel and colonic transit.

Gender-related differences in slowing colonic transit by a 5-HT3 antagonist in subjects with diarrhea-predominant irritable bowel syndrome.

OBJECTIVE: To evaluate the influence of gender on the effect of a 5-HT3 antagonist, alosetron, 1 mg b.i.d., on GI and colonic transit in D-IBS. METHODS: Thirty patients (15 male, 15 female) with D-IBS received 1 mg b.i.d. alosetron for 6 wk. Transit was measured by scintigraphy at baseline and at the end of treatment. RESULTS: Alosetron, 1 mg b.i.d., significantly retarded small bowel and, proximal and overall colonic transit in the 30 patients with D-IBS. The effect of alosetron on the primary endpoint, colonic geometric center at 24 h, was significantly greater in females than in males (p < 0.05). However, two females showed no slowing of colonic transit on treatment. Among male patients, two of 15 had a slowing of colonic transit at 24 h that was greater than the mean change in female patients, suggesting responsiveness to alosetron among a subgroup of males. CONCLUSION: A 5-HT3 antagonist, alosetron, significantly retards small intestinal and colonic transit in diarrhea-predominant IBS patients, with significantly greater female to male responsiveness. Gender partly contributes to differences in the serotonergic control of intestinal and colonic transit in patients with D-IBS.

Validation of a stable isotope gastric emptying test for normal, accelerated or delayed gastric emptying.

To validate a 13C-Spirulina platensis breath test for measurement of accelerated or delayed gastric emptying, we measured gastric emptying of egg containing 13C-S. platensis and 99mTc-sulphur colloid by breath 13 CO2 every 15 min over 3 h and scintigraphy every 15-30 min over 5 h in 57 healthy volunteers. Thirty-three received no treatment, 10 received erythromycin, and 14 atropine. A generalized linear regression model predicted half-emptying time by scintigraphy (t1/2S) from breath 13CO2 (t1/2B) data. Accuracy was assessed by standard deviation (SD) of differences between t1/2S and t1/2B and by receiver operating characteristic (ROC) curves. Regression models using breath samples at baseline, and 45, 90, 105 and 120 min, predicted t1/2B (mean +/- SD) at 118 +/- 59 min, similar to t1/2S (118 +/- 67 min). Correlation between t1/2B and t1/2S was significant (r=0.88; P < 0.0001). Differences between t1/2S and t1/2B were: 18-19.2 min for t1/2 < 70-150 min, and 68.3 min for t1/2 > 150 min. Breath test detected abnormal emptying with a sensitivity of 86% and specificity of 80%. Thus, the 13C-S. platensis test measures gastric emptying t1/2 for solids, which is accelerated or delayed to mimic a range of conditions from dumping syndrome to severe gastroparesis, with high sensitivity and specificity. Additional breath samples are needed to increase sensitivity in detecting accelerated gastric emptying.

Motilides accelerate regional gastrointestinal transit in the dog.

BACKGROUND: Motilides have prokinetic effects on the upper gut during fasting, increasing the strength of antral contractions and stimulating gastroduodenal phase 3 sequences. Effects on the distal gut, and postprandially, are less well documented. AIM: To evaluate dose-response effects of motilin and erythromycin on gastric emptying, small bowel and colonic transit in the dog using a validated scintigraphic technique. METHODS: For gastric emptying and small bowel transit, 99mTc labelled beads were added to a meal of dog chow (450 kcal). Regional colonic transit was measured by 111In labelled beads placed in a capsule which dissolved and released radiation into the proximal colon. Scintiscans were taken at regular intervals and indices of whole-gut transit were calculated. Drugs were given by slow intravenous administration. RESULTS: In the doses used, motilin accelerated regional colonic transit but did not hasten gastric emptying or small bowel transit. Single or repeated doses of motilin had similar effects on colonic transit. Erythromycin accelerated gastric emptying, small bowel transit and regional colonic transit. CONCLUSIONS: Motilin receptors are apparently present in the canine small bowel and colon. Postprandially, motilides accelerate transit in the distal gut.

Scintigraphic measurement of regional gastrointestinal transit in the dog.

Scintigraphic techniques can measure sequentially gastric emptying, small bowel transit, and colonic transit in humans, and comparable methods for experimental studies in animals would be useful. We developed such a method in dogs and examined the effects of prokinetic drugs on regional transit. Two isotopes were given to fasting dogs. Polystyrene pellets labeled with 99mTc were mixed in a can of dog food and 111In- labeled pellets were given in a gelatin capsule coated with a pH-sensitive polymer, designed to dissolve in the distal bowel. Gamma camera images were obtained for up to 24 h. Prokinetic drugs were given by intravenous injection. Duplicate baseline studies showed good agreement in seven dogs. In a second group (n = 4), intra- and interanimal variabilities were established. Two novel prokinetic drugs (AU-116 and AU-130) accelerated small bowel and colonic transit. A simple noninvasive method for measuring whole gut transit in dogs was developed and validated. Two new prokinetics accelerated small bowel and colonic transit.

Medium-term effects of a new 5HT3 antagonist, alosetron, in patients with carcinoid diarrhoea.

BACKGROUND: Carcinoid diarrhoea is associated with rapid small bowel and proximal colonic transit. Intravenous administration of a serotonin type 3 receptor (5HT3) antagonist restores postprandial colonic tone towards normal in carcinoid patients. AIMS: To evaluate the medium-term effects of an oral 5HT3 antagonist, alosetron, on symptoms, stool fat, and transit in patients with carcinoid diarrhoea. METHODS: In 27 patients with carcinoid diarrhoea, symptoms were recorded daily and gastrointestinal transit was measured by scintigraphy in a three dose (0.1, 0.5, 2.0 mg, twice daily), randomised (1:1:1), parallel group, four week study. Placebo was given during the first week. Loperamide (2 mg capsules) was used as rescue medication. RESULTS: There were numerical improvements in median diarrhoea score, stool weight, loperamide use, and overall colonic transit at four hours, but no overall significant drug effect was shown. Alosetron reduced the proximal colon emptying rate (p < 0.05 in 20 evaluable comparisons), but did not significantly alter small bowel transit. CONCLUSIONS: Alosetron retardation of proximal colonic emptying in patients with carcinoid diarrhoea confirms the potential role of a 5HT3 mechanism in this disorder. Doses of alosetron higher than 2.0 mg twice daily will be required for symptomatic benefit in carcinoid diarrhoea.

Influence of H. pylori infection on gastric motor and sensory function in asymptomatic volunteers.

The effect of H. pylori infection on gastric motility and sensation is unclear. Our hypothesis is that H. pylori infection increases gastric sensation and reduces gastric accommodation and emptying. In eight H. pylori-positive and eight H. pylori-negative asymptomatic subjects, infection was proven by antral histology or culture. We evaluated: (1) gastric emptying of solids, (2) proximal gastric compliance, (3) fasting and postprandial proximal gastric tone and phasic contractions, (4) gastric sensation during balloon inflations or ingestion of cold water, and (5) abdominal vagal function. H. pylori infection was associated with lower gastric accommodation (median 75% postprandial increase in barostat balloon volume compared to fasting) when compared to the accommodation in uninfected volunteers (median 211% change from fasting). One H. pylori-positive subject had an abnormal abdominal vagal function test and her gastric accommodation response was reduced. Other motor and sensory functions in the two groups were similar. In asymptomatic volunteers, H. pylori infection and gastritis result in reduced accommodation (diastolic dysfunction) but no change in overall sensation or motor functions of the stomach.

Effects of glucagon on postprandial carbohydrate metabolism in nondiabetic humans.

The present experiments sought to determine whether glucagon concentrations mimicking those observed in people with diabetes mellitus alter postprandial carbohydrate metabolism in nondiabetic humans. We measured the gastric emptying of solids and liquids, the systemic rate of appearance of ingested glucose, and endogenous glucose production either when postprandial suppression of glucagon was prevented by infusing glucagon at a rate of 0.65 ng/kg/min, when postprandial glucagon concentrations were elevated by infusing glucagon at a rate of 3.0 ng/kg/min, or when postprandial suppression of glucagon was permitted by infusion of saline. Despite marked differences in glucagon concentrations, postprandial glucose and insulin concentrations did not differ on any occasion. Although gastric emptying of liquids and solids was comparable on all three occasions, the high-dose, but not the low-dose, glucagon infusion caused a slight delay in the systemic appearance of ingested glucose and a significant decrease (P < .01) in postprandial D-xylose concentrations, suggesting a delay in carbohydrate absorption. However, this was offset by an increase (P < .05) in endogenous glucose production, resulting in no difference in postprandial glucose appearance. We conclude that in the absence of insulin deficiency, neither a lack of suppression of glucagon nor an elevation of glucagon to levels encountered in uncontrolled diabetes mellitus cause postprandial hyperglycemia in nondiabetic humans.

Rapid gastric emptying in patients with functional diarrhea.

OBJECTIVE: To analyze our experience in patients with chronic diarrhea by using a noninvasive transit study that measures gastric emptying as well as small bowel and colonic transit. MATERIAL AND METHODS: Results from 94 consecutive transit tests, for which diarrhea was the main indication, were reviewed and correlated with the final classification of patients as having an organic or nonorganic disorder. RESULTS: Sixty patients were considered to have a nonorganic cause of diarrhea, of whom 15 had previously undergone cholecystectomy. The other 34 patients were considered to have diarrhea on the basis of an organic diagnosis. Gastric emptying was more often rapid in patients with a nonorganic cause (P < 0.05), but not if cholecystectomy had been performed previously. Small bowel transit was fast more often in patients with organic diarrhea than in those with no organic cause of the diarrhea (P < 0.05); colonic transits showed no significant differences among groups. CONCLUSION: The findings implicate a motor abnormality of the upper gut, rapid gastric emptying, as a pathophysiologic mechanism of functional bowel disorders with diarrhea. The results imply that additional prospective observations should be worth-while.

Effect of cholecystokinin octapeptide and atropine on human colonic motility, tone, and transit.

The role of cholecystokinin (CCK) in postprandial control of colonic motility is controversial. To test the hypothesis that CCK stimulates colonic tone, motility, and transit we measured these colonic functions in 16 healthy subjects using intraluminal manometry, barostatic balloon measurements, and radioscintigraphy. This was a randomized-order, double-blind, sequential study design in each subject of saline and either atropine (0.01 mg/kg stat and 0.01 mg/kg/hr by infusion) or CCK-octapeptide (OP, 30 ng/kg stat and 60 ng/kg/hr by infusion). Atropine was used as control to demonstrate responsiveness of selected parameters of colonic motility. Atropine significantly reduced whole colon (change from fasting = 52 +/- 11%) and left colon (change from fasting 61 +/- 8%) phasic pressure activity and transverse colon tone (change from fasting 159 +/- 40%); CCK-OP had no significant effects on phasic contractility, tone or transit. Thus, a CCK-OP infusion that maximally stimulates pancreatic exocrine secretion and gallbladder contraction has no effect on motor function or transit in prepared colon of healthy subjects.

Hyperventilation alters colonic motor and sensory function: effects and mechanisms in humans.

UNLABELLED: BACKGROUND & AIMS. Hyperventilation-induced hypocapnia affects hemodynamic function and enhances colonic motility. The aims of this study were to determine the effects of hypocapnic hyperventilation on colonic motility and sensation in health and to explore the putative neurohumoral mechanisms. METHODS: In experiment 1, colonic tone, sensation, plasma levels of cortisol, beta-endorphin, selected gut neuropeptides, norepinephrine, epinephrine, and splanchnic blood volume were measured during two sequences of hypocapnic hyperventilation. In experiment 2, colonic tone and sensation were assessed during eucapnic hyperventilation and abdominal compression. RESULTS: Hypocapnic hyperventilation, but not eucapnic hyperventilation or abdominal compression, significantly increased colonic tone and sensitivity to balloon distention (P = 0.017) without altering humoral mediators or splanchnic blood volume. Plasma norepinephrine level increased (P = 0.017) and splanchnic blood volume decreased (P = 0.028) during 5 minutes after hyperventilation, consistent with homeostatic responses. CONCLUSIONS: Increased colonic tone and sensation during hypocapnic hyperventilation are not caused by colonic compression. These effects of hyperventilation are not mediated humorally but may result from direct metabolic effects of hypocapnia on colonic muscle or from changes in central autonomic control of colonic smooth muscle.

Relation between fat malabsorption and transit abnormalities in human carcinoid diarrhea.

BACKGROUND & AIMS: Fat and complex carbohydrates in the distal bowel activate "brakes" inhibiting upper gut motility. The hypothesis of this study was that rapid transit carcinoid diarrhea in association with steatorrhea results in impairment of gastric emptying. METHODS: Fifteen patients with carcinoid diarrhea without prior gastrointestinal resection or whose small bowel resection was limited to < 100 cm of ileum were studied. Gastrointestinal transit was measured scintigraphically with a standardized meal. Percentage of ingested fat excretion was calculated. RESULTS: Mean length of small bowel resected was 33 cm, and mean 24-hour urine 5-hydroxyindoleacetic acid was 120 mg. Fourteen patients had increased daily stool weights, and 10 had increased stool fat excretion (mean, 13%). Transit was accelerated in the small bowel in 14 and in the colon in all patients. The lag time for gastric emptying was prolonged in 2 patients who had no previous resection. Gastric emptying rate was accelerated in 5, normal in 7, and delayed in 3 patients. CONCLUSIONS: Ileal and colonic brakes do not seem to delay gastric emptying in patients with carcinoid diarrhea associated with rapid transit and mild to moderate steatorrhea.

A pilot study of splenic and whole body retention of autologous radiolabeled leukocytes in the assessment of severity in inflammatory colitis.

OBJECTIVE: To assess the splenic and whole body retention of radiolabeled autologous leukocytes over 24 or 48 h as measures of the severity of colitis. METHODS: Eleven patients with colitis underwent standardized clinical, endoscopic, histological, and 111In-labeled leukocyte scintigraphy. A logistic discriminant analysis was used to estimate weighting factors for morphological indices, serum albumen, and stool excretion of 111In over 24 h that predicted the clinical assessment of severity. Subsequently, Spearman rank correlation analysis estimated associations among reductions in spleen and whole body radioactivity and the derived indices of inflammation. RESULTS: The reduction in spleen counts over 24 h correlates significantly with morphological indices (rs = 0.83, p < 0.005) and with serum albumen and stool 111In (functional index, rs = 0.77, p < 0.01). Similarly, the reduction in whole body 111In over 48 h correlates significantly with the combined index (rs = 0.8) and with the morphological and functional index separately (rs = 0.72 and 0.79, respectively). CONCLUSION: This pilot study identified weighting factors for morphological and functional indices in assessing severity of colitis; reduction in whole body and splenic retention of radioactivity was sufficient for evaluation of severity of colitis without the need for stool collections.

Mechanism of accelerated gastric emptying of liquids and hyperglycemia in patients with type II diabetes mellitus.

BACKGROUND & AIMS: The roles of hyperglycemia in diabetic gastroparesis and gastric delivery in postprandial hyperglycemia of diabetic patients are unclear. The aims of this study were to assess gastric emptying and its relation to postprandial glucose metabolism in patients with asymptomatic non-insulin-dependent diabetes mellitus (NIDDM) and no autonomic neuropathy and to identify motor mechanisms responsible for any accelerated gastric emptying. METHODS: Autonomic function, gastric emptying, postprandial glucose metabolism, and hormone levels (glucagon, insulin, cholecystokinin, glucose-dependent insulinotropic polypeptide, neurotensin, and peptide YY) were assessed in healthy volunteers and patients with NIDDM. In a second study, gastric tone and motility were measured in patients with accelerated gastric emptying and in controls. RESULTS: Gastric emptying of solids did not differ in the two groups, but liquids emptied faster in patients with NIDDM (P < 0.02). The rate of entry of ingested glucose into the systemic circulation was similar, but higher postprandial glucagon and lower insulin concentrations led to greater (P < 0.01) postprandial hepatic glucose release. Levels of other enteropeptides, gastric accommodation, and antral motility were similar, but patients with NIDDM had greater proximal gastric phasic contractions than controls (P < 0.05). CONCLUSIONS: Excessive hepatic glucose release, not rapid entry of ingested glucose, is the primary cause of postprandial hyperglycemia in patients with NIDDM. Accelerated gastric emptying in patients with nonneuropathic NIDDM is associated with increased proximal stomach phasic contractions.

Differential regional effects of octreotide on human gastrointestinal motor function.

The effects of octreotide on regional motor function in the human gut are unclear. In a randomised, blinded study the effects of octreotide (50 micrograms, subcutaneously, three times daily) and placebo on gastric, small bowel, and colonic transit, and colonic motility and tone were assessed in 12 healthy volunteers whose colon had been cleansed. Octreotide accelerated initial gastric emptying (p = 0.05), inhibited small bowel transit (p < 0.01), and reduced ileocolonic bolus transfers (p < 0.05). Colonic transit was unaltered by octreotide; the postprandial colonic tonic response was inhibited (p < 0.05 v placebo), whereas colonic phasic pressure activity was increased by octreotide (p < 0.05 v placebo). These data support the use of octreotide in diarrhoeal states but not in diseases that cause small bowel stasis and bacterial overgrowth. Simultaneous measurements of colonic transit, tone, and phasic contractility are valid in studying the effects of pharmacological changes and may be applicable to the study of the human colon in health and disease.