Dose-related effects of intraduodenal quinine on plasma glucose, glucoregulatory hormones and gastric emptying of a nutrient drink, and energy intake, in men with type 2 diabetes: a double-blind, randomised, crossover study.

Aims/hypothesis: Quinine, when administered intraduodenally to activate bitter-taste receptors, in a dose of 600 mg, stimulates glucagon-like peptide-1 (GLP-1) and insulin, slows gastric emptying and lowers postprandial glucose in healthy people, with consequent implications for the management of type 2 diabetes; the effect of quinine on energy intake is uncertain. We have investigated the dose-related effects of quinine on postprandial blood glucose levels and energy intake in people with type 2 diabetes.

Methods: Male participants with type 2 diabetes (age: 68±5 years; HbA: 49.

Effects of intraduodenal or intragastric administration of a bitter hop extract (Humulus lupulus L.), on upper gut motility, gut hormone secretion and energy intake in healthy-weight men.

Gastrointestinal functions, particularly pyloric motility and the gut hormones, cholecystokinin and peptide YY, contribute to the regulation of acute energy intake. Bitter tastants modulate these functions, but may, in higher doses, induce GI symptoms. The aim of this study was to evaluate the effects of both dose and delivery location of a bitter hop extract (BHE) on antropyloroduodenal pressures, plasma cholecystokinin and peptide YY, appetite perceptions, gastrointestinal symptoms and energy intake in healthy-weight men.

Comparative Effects of Intragastric and Intraduodenal Administration of Quinine on the Plasma Glucose Response to a Mixed-Nutrient Drink in Healthy Men: Relations with Glucoregulatory Hormones and Gastric Emptying.

Background: In preclinical studies, bitter compounds, including quinine, stimulate secretion of glucoregulatory hormones [e.g., glucagon-like peptide-1 (GLP-1)] and slow gastric emptying, both key determinants of postprandial glycemia.

Intragastric administration of leucine and isoleucine does not reduce the glycaemic response to, or slow gastric emptying of, a carbohydrate-containing drink in type 2 diabetes.

Aims: In healthy individuals, intragastric administration of the branched-chain amino acids, leucine and isoleucine, diminishes the glycaemic response to a mixed-nutrient drink, apparently by stimulating insulin and slowing gastric emptying, respectively. This study aimed to evaluate the effects of leucine and isoleucine on postprandial glycaemia and gastric emptying in type-2 diabetes mellitus (T2D).

Methods: 14 males with T2D received, on 3 separate occasions, in double-blind, randomised fashion, either 10 g leucine, 10 g isoleucine or control, intragastrically 30 min before a mixed-nutrient drink (500 kcal; 74 g carbohydrates, 18 g protein, 15 g fat).

Effects of L-Phenylalanine on Energy Intake and Glycaemia-Impacts on Appetite Perceptions, Gastrointestinal Hormones and Gastric Emptying in Healthy Males.

In humans, phenylalanine stimulates plasma cholecystokinin (CCK) and pyloric pressures, both of which are important in the regulation of energy intake and gastric emptying. Gastric emptying is a key determinant of postprandial blood glucose. We evaluated the effects of intragastric phenylalanine on appetite perceptions and subsequent energy intake, and the glycaemic response to, and gastric emptying of, a mixed-nutrient drink.

Effects of intraduodenal coadministration of lauric acid and leucine on gut motility, plasma cholecystokinin, and energy intake in healthy men.

The fatty acid, lauric acid (C12), and the amino acid, leucine (Leu) stimulate gut hormones, including CCK, associated with suppression of energy intake. In our recent study, intraduodenal infusion of a combination of C12 and l-tryptophan, at loads that individually did not affect energy intake, reduced energy intake substantially, associated with much greater stimulation of CCK. We have now investigated whether combined administration of C12 and Leu would enhance the intake-suppressant effects of each nutrient, when given at loads that each suppress energy intake individually.

Intragastric administration of the bitter tastant quinine lowers the glycemic response to a nutrient drink without slowing gastric emptying in healthy men.

The rate of gastric emptying and the release of gastrointestinal (GI) hormones are major determinants of postprandial blood-glucose concentrations and energy intake. Preclinical studies suggest that activation of GI bitter-taste receptors potently stimulates GI hormones, including glucagon-like peptide-1 (GLP-1), and thus may reduce postprandial glucose and energy intake. We evaluated the effects of intragastric quinine on the glycemic response to, and the gastric emptying of, a mixed-nutrient drink and the effects on subsequent energy intake in healthy men.

Effects of Duodenal Infusion of Lauric Acid and L-Tryptophan, Alone and Combined, on Fasting Glucose, Insulin and Glucagon in Healthy Men.

The fatty acid, lauric acid ('C12'), and the amino acid, tryptophan ('Trp'), when given intraduodenally at loads that individually do not affect energy intake, have recently been shown to stimulate plasma cholecystokinin, suppress ghrelin and reduce energy intake much more markedly when combined. Both fatty acids and amino acids stimulate insulin secretion by distinct mechanisms; fatty acids enhance glucose-stimulated insulin secretion, while amino acids may have a direct effect on pancreatic β cells. Therefore, it is possible that, by combining these nutrients, their effects to lower blood glucose may be enhanced.

Effects of Intraduodenal Infusion of the Bitter Tastant, Quinine, on Antropyloroduodenal Motility, Plasma Cholecystokinin, and Energy Intake in Healthy Men.

Background/aims: Nutrient-induced gut hormone release (eg, cholecystokinin [CCK]) and the modulation of gut motility (particularly pyloric stimulation) contribute to the regulation of acute energy intake. Non-caloric bitter compounds, including quinine, have recently been shown in cell-line and animal studies to stimulate the release of gastrointestinal hormones by activating bitter taste receptors expressed throughout the gastrointestinal tract, and thus, may potentially suppress energy intake without providing additional calories. This study aims to evaluate the effects of intraduodenally administered quinine on antropyloroduodenal pressures, plasma CCK and energy intake.

Effects of intraduodenal administration of lauric acid and L-tryptophan, alone and combined, on gut hormones, pyloric pressures, and energy intake in healthy men.

Background: The fatty acid, lauric acid ('C12'), and the amino acid, L-tryptophan ('Trp'), modulate gastrointestinal functions including gut hormones and pyloric pressures, which are important for the regulation of energy intake, and both potently suppress energy intake.

Objective: We hypothesized that the intraduodenal administration of C12 and Trp, at loads that do not affect energy intake individually, when combined will reduce energy intake, which is associated with greater modulation of gut hormones and pyloric pressures.

Design: Sixteen healthy, lean males (age: 24 ± 1.

Intraduodenal Administration of L-Valine Has No Effect on Antropyloroduodenal Pressures, Plasma Cholecystokinin Concentrations or Energy Intake in Healthy, Lean Men.

Whey protein is rich in the branched-chain amino acids, L-leucine, L-isoleucine and L-valine. Thus, branched-chain amino acids may, at least in part, mediate the effects of whey to reduce energy intake and/or blood glucose. Notably, 10 g of either L-leucine or L-isoleucine, administered intragastrically before a mixed-nutrient drink, lowered postprandial blood glucose, and intraduodenal infusion of L-leucine (at a rate of 0.

Effects of Intragastric Administration of Tryptophan on the Blood Glucose Response to a Nutrient Drink and Energy Intake, in Lean and Obese Men.

Tryptophan stimulates plasma cholecystokinin and pyloric pressures, both of which slow gastric emptying. Gastric emptying regulates postprandial blood glucose. Tryptophan has been reported to decrease energy intake.

Comparative effects of intraduodenal whey protein hydrolysate on antropyloroduodenal motility, gut hormones, glycemia, appetite, and energy intake in lean and obese men.

Background: In lean individuals, intraduodenal protein and lipid modulate gastrointestinal motor and hormone functions and reduce energy intake in a load-dependent manner; protein also stimulates insulin, with modest effects on reducing blood glucose. The effect of intraduodenal lipid on gastrointestinal motor and hormone responses is diminished in obesity; whether the effects of protein are also attenuated remains unclear.

Objectives: The objectives of this study were to characterize the load-dependent effects of intraduodenal whey protein hydrolysate on antropyloroduodenal pressures, gut hormones, glycemia, appetite, and energy intake in obese subjects and to compare the responses to the higher protein load with those in lean subjects.