Rate of gastric emptying is a determinant of postprandial hypotension in non-insulin-dependent diabetes mellitus.

1. Postprandial hypotension is now recognized as an important clinical problem, particularly in the elderly and in patients with autonomic dysfunction. The mechanisms responsible are poorly understood; however, impaired regulation of splanchnic blood flow and the release of gastrointestinal hormones appear to be important. The effect of gastric emptying on the magnitude of the postprandial fall in blood pressure has not been evaluated. 2. The aim of this study was to determine whether there is a relationship between changes in blood pressure and the rate of gastric emptying after ingestion of 75 g of glucose in patients with non-insulin-dependent diabetes mellitus (NIDDM) and both young and older normal subjects. Sixteen patients with recently diagnosed NIDDM, median age 57 (39-79) years, 10 'young' subjects with a median age of 23 (19-26) years and nine 'older' subjects, median age 48 (40-68) years, were measured simultaneously for gastric emptying of 75 g of glucose in 350 ml of water blood pressure and blood glucose concentrations, commencing at approximately 10.00 hours after an overnight fast. Measurements of blood pressure were made in the sitting position immediately before glucose ingestion and at 15 min intervals up to 180 min. 3. Gastric emptying of glucose was not significantly different between the three groups [50% emptying time (T50): 95 +/- 7.3 min in patients with NIDDM compared with 120 +/- 13.2 min in the 'young' group and 97 +/- 8.1 min in the 'older' group]. There was a significant fall in mean blood pressure after the glucose load in the patients with NIDDM (P < 0.0001) and the 'older' normal subjects (P < 0.05), but not the 'young' normal subjects. Postprandial hypotension (fall in systolic blood pressure > or = 20 mmHg) was evident in seven (44%) patients with NIDDM and three (33%) 'older' normal subjects. The area under the change in mean blood pressure curve was related significantly to the gastric emptying T50 (r = 0.67, P < 0.005) in the patients with NIDDM, but not in either control group. 4. In conclusion, in patients with recently diagnosed NIDDM the fall in blood pressure after an oral glucose load is (i) greater than in both young and older normal subjects and (ii) related to the rate of gastric emptying.

Gastric emptying in early noninsulin-dependent diabetes mellitus.

UNLABELLED: The aims of this study were to determine in early noninsulin-dependent diabetes mellitus (NIDDM): (a) the prevalence of disordered gastric emptying of glucose; (b) the relationship between the blood glucose response to an oral glucose load and gastric emptying; and (c) the relationship between appetite and gastric emptying. METHODS: Sixteen patients (ages 39-79 yr) with recently diagnosed NIDDM consumed 350 ml water containing 75 g glucose and 99mTc-sulfur colloid while sitting in front of a gamma camera. Blood glucose concentrations were monitored immediately before and after the drink. Hunger and fullness were evaluated using visual analog scales. The results were compared to those obtained in 13 normal subjects of similar age and body mass index. All patients and control subjects were white and non-Hispanic. RESULTS: Gastric emptying was slightly slower in the NIDDM patients when compared to the control subjects (retention at 180 min 15.9 +/- 2.3% versus 3.8 +/- 1.0%, p < 0.001), but there was no significant difference in the 50% emptying time between the two groups. In the NIDDM patients, there was an inverse relationship between the magnitude of the increase in the blood glucose concentration and gastric emptying, e.g., between the area under the curve for blood glucose from 0-60 min and the intragastric retention of the drink at 60 min (r = -0.60, p < 0.05). In the NIDDM patients, fullness was greater (p < 0.005) both before and after the drink, and the score for hunger at 30 min was inversely related to the rate of gastric emptying (r = -0.52, p < 0.05). CONCLUSION: In patients with early NIDDM, gastric emptying of 75 g glucose is similar to that of normal subjects and is a significant determinant of the glycemic response.

Effects of cisapride on gastric emptying of oil and aqueous meal components, hunger, and fullness.

To evaluate the effects of cisapride on gastric emptying of extracellular fat and hunger and fullness 10 volunteers consumed a meal consisting of 60 ml technectium-99m (99mTc)-V-thiocyanate labelled olive oil and 290 ml indium-113m (113mIn) labelled soup after taking cisapride (10 mg four times daily orally) and placebo, each for four days, in randomised, double blind fashion. Gastric emptying was quantified scintigraphically. Hunger and fullness before and after the meal were evaluated using visual analogue scales. Cisapride accelerated gastric emptying of oil and aqueous components by reducing the lag phase mean (SEM) (20.3 (7.0) min v 40.7 (4.1) min (p < 0.05) for oil and 4.1 (2.5) min v 10.0 (3.1) min (p < 0.05) for aqueous). Cisapride had no effect on the post-lag emptying rate of oil. Treatment with cisapride was associated with reduced retention of oil in the proximal stomach (p < 0.05). Subjects were more hungry before ingestion of the meal while receiving cisapride (6.7 (0.9) v 3.9 (0.7), p < 0.001). The scores for hunger at 120 and 180 minutes were inversely related to gastric emptying of oil on both cisapride (r > -0.62, p < 0.05) and placebo (r > -0.86, p < 0.001). Fullness increased after the meal while receiving placebo (p < 0.01), but not cisapride and postprandial fullness was less with cisapride at (30 min; 0.4 (0.3) v 3.3 (1.0), p < 0.05). With placebo, but not cisapride, the score for fullness at 15 minutes was inversely related to emptying of the aqueous phase (r = 0.68, p < 0.05). These results show that in normal volunteers after ingestion of an oil/aqueous meal: (a) postprandial hunger is inversely related to gastric emptying of oil, while fullness is inversely related to gastric emptying of the aqueous phase, (b) cisapride affects the intragastric distribution and accelerates gastric emptying of both oil and aqueous meal components, and (c) cisapride increases preprandial hunger and reduces postprandial fullness.

Gastric emptying of oil and aqueous meal components in pancreatic insufficiency: effects of posture and on appetite.

The aims of this study were to evaluate the effects of posture on gastric emptying, intragastric distribution, and satiation after a meal containing oil and aqueous phases in patients with exocrine pancreatic insufficiency. Five patients with cystic fibrosis (CF) consumed 60 ml 99mTc-labeled (V)-thiocyanate olive oil and 290 ml 113mIn-labeled diethylenetriaminepentaacetic acid soup while sitting and while lying in the left lateral decubitus position. Hunger and fullness before and after the meal were recorded. Results were compared with those obtained in 11 normal volunteers. In both postures emptying of oil was faster (P < 0.01) in CF patients. Emptying of the aqueous phase was faster (P < 0.01) in CF patients in the decubitus position. In normal subjects there was no overall difference in emptying of oil between the two postures, whereas emptying of the aqueous phase was delayed (P < 0.01) in the decubitus position. In CF patients emptying of oil was faster (P < 0.01) in the decubitus position, and emptying of the aqueous phase was only slightly faster (P < 0.05) in the sitting position. For both postures there was greater retention (P < 0.05) of oil in the proximal stomach in normal subjects than CF patients. Hunger decreased (P < 0.05) after the meal in the control subjects, but there was no change in CF patients. These results indicate that in CF patients with pancreatic exocrine insufficiency 1) gastric emptying of nonhomogenized fat is faster than normal, 2) gravity affects gastric emptying of oil, and 3) effects of a fatty meal on hunger are reduced.

Stereospecific effects of tryptophan on gastric emptying and hunger in humans.

The amino acid tryptophan (tryp) is a potent inhibitor of gastric emptying in both animals and humans. Animal studies suggest that this effect may be specific for the L-enantiomer. The effects of D- and L-tryptophan on gastric emptying, intragastric distribution and appetite in humans were evaluated. Ten volunteers ingested 300 mL of either L-tryp (50 mmol/L), D-tryp (50 mmol/L) or normal saline labelled with 99mTc sulfur colloid on three occasions, separated by between 3 and 7 days. Hunger and fullness were measured with a visual analogue scale at -2, 15, 30 and 60 min after ingestion of each drink. Saline emptied faster from the stomach than both L-tryp and D-tryp (P < 0.05) and D-tryp emptied faster than L-tryp (P < 0.005). Emptying from the proximal stomach was fastest for saline (P < 0.05) and faster for D-tryp than L-tryp (P < 0.005). Emptying from the distal stomach was faster for saline than both D- and L-tryp (P < 0.05). A reduction in hunger (P < 0.05) and a non-significant trend for an increase in fullness were observed after all three drinks. At 60 min, fullness was greater after L-tryp than after ingestion of D-tryp (P < 0.01). These observations indicate that the effect of tryptophan on gastric emptying in humans is stereospecific, consistent with the concept that stereospecific receptors for tryptophan exist in the human small intestine.