scholarly journals Comparative Effects of the Branched-Chain Amino Acids, Leucine, Isoleucine and Valine, on Gastric Emptying, Plasma Glucose, C-Peptide and Glucagon in Healthy Men

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1613
Author(s):  
Rachel A. Elovaris ◽  
Vida Bitarafan ◽  
Shahram Agah ◽  
Sina S. Ullrich ◽  
Kylie Lange ◽  
...  
Keyword(s):  
Amino Acids ◽  
Blood Glucose ◽  
Gastric Emptying ◽  
Plasma Glucose ◽  
Branched Chain Amino Acids ◽  
Postprandial Blood Glucose ◽  
Intragastric Administration ◽  
C Peptide ◽  
Healthy Men ◽  
Branched Chain

(1) Background: Whey protein lowers postprandial blood glucose in health and type 2 diabetes, by stimulating insulin and incretin hormone secretion and slowing gastric emptying. The branched-chain amino acids, leucine, isoleucine and valine, abundant in whey, may mediate the glucoregulatory effects of whey. We investigated the comparative effects of intragastric administration of leucine, isoleucine and valine on the plasma glucose, C-peptide and glucagon responses to and gastric emptying of a mixed-nutrient drink in healthy men. (2) Methods: 15 healthy men (27 ± 3 y) received, on four separate occasions, in double-blind, randomised fashion, either 10 g of leucine, 10 g of isoleucine, 10 g of valine or control, intragastrically, 30 min before a mixed-nutrient drink. Plasma glucose, C-peptide and glucagon concentrations were measured before, and for 2 h following, the drink. Gastric emptying of the drink was quantified using 13C-acetate breath-testing. (3) Results: Amino acids alone did not affect plasma glucose or C-peptide, while isoleucine and valine, but not leucine, stimulated glucagon (p < 0.05), compared with control. After the drink, isoleucine and leucine reduced peak plasma glucose compared with both control and valine (all p < 0.05). Neither amino acid affected early (t = 0–30 min) postprandial C-peptide or glucagon. While there was no effect on overall gastric emptying, plasma glucose at t = 30 min correlated with early gastric emptying (p < 0.05). (4) Conclusion: In healthy individuals, leucine and isoleucine lower postprandial blood glucose, at least in part by slowing gastric emptying, while valine does not appear to have an effect, possibly due to glucagon stimulation.

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

2020 ◽  
Vol 318 (2) ◽  
pp. R263-R273 ◽  
Author(s):  
Vida Bitarafan ◽  
Penelope C. E. Fitzgerald ◽  
Tanya J. Little ◽  
Wolfgang Meyerhof ◽  
Karen L. Jones ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Gastric Emptying ◽  
Energy Intake ◽  
Plasma Glucose ◽  
Postprandial Blood Glucose ◽  
Intragastric Administration ◽  
Glycemic Response ◽  
Experimental Conditions ◽  
Double Blind ◽  
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. The study consisted of 2 parts: part A included 15 lean men, and part B included 12 lean men (aged 26 ± 2 yr). In each part, participants received, on 3 separate occasions, in double-blind, randomized fashion, intragastric quinine (275 or 600 mg) or control, 30 min before a mixed-nutrient drink ( part A) or before a buffet meal ( part B). In part A, plasma glucose, insulin, glucagon, and GLP-1 concentrations were measured at baseline, after quinine alone, and for 2 h following the drink. Gastric emptying of the drink was also measured. In part B, energy intake at the buffet meal was quantified. Quinine in 600 mg (Q600) and 275 mg (Q275) doses alone stimulated insulin modestly ( P < 0.05). After the drink, Q600 and Q275 reduced plasma glucose and stimulated insulin ( P < 0.05), Q275 stimulated GLP-1 ( P < 0.05), and Q600 tended to stimulate GLP-1 ( P = 0.066) and glucagon ( P = 0.073) compared with control. Quinine did not affect gastric emptying of the drink or energy intake. In conclusion, in healthy men, intragastric quinine reduces postprandial blood glucose and stimulates insulin and GLP-1 but does not slow gastric emptying or reduce energy intake under our experimental conditions.

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

Nutrients ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 99 ◽  
Author(s):  
Rachel A. Elovaris ◽  
Penelope C. E. Fitzgerald ◽  
Vida Bitarafan ◽  
Sina S. Ullrich ◽  
Michael Horowitz ◽  
...  
Keyword(s):  
Amino Acids ◽  
Blood Glucose ◽  
Energy Intake ◽  
Branched Chain Amino Acids ◽  
World Health ◽  
Postprandial Blood Glucose ◽  
Saline Control ◽  
Intraduodenal Infusion ◽  
Plasma Cholecystokinin ◽  
Branched Chain

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 0.45 kcal/min, total: 9.9 g) lowered fasting blood glucose and reduced energy intake from a subsequent meal. Whether L-valine affects energy intake, and the gastrointestinal functions involved in the regulation of energy intake, as well as blood glucose, in humans, is currently unknown. We investigated the effects of intraduodenally administered L-valine on antropyloroduodenal pressures, plasma cholecystokinin, blood glucose and energy intake. Twelve healthy lean men (age: 29 ± 2 years, BMI: 22.5 ± 0.7 kg/m2) were studied on 3 separate occasions in randomised, double-blind order. Antropyloroduodenal pressures, plasma cholecystokinin, blood glucose, appetite perceptions and gastrointestinal symptoms were measured during 90-min intraduodenal infusions of L-valine at 0.15 kcal/min (total: 3.3 g) or 0.45 kcal/min (total: 9.9 g), or 0.9% saline (control). Energy intake from a buffet-meal immediately after the infusions was quantified. L-valine did not affect antral, pyloric (mean number; control: 14 ± 5; L-Val-0.15: 21 ± 9; L-Val-0.45: 11 ± 4), or duodenal pressures, plasma cholecystokinin (mean concentration, pmol/L; control: 3.1 ± 0.3; L-Val-0.15: 3.2 ± 0.3; L-Val-0.45: 3.0 ± 0.3), blood glucose, appetite perceptions, symptoms or energy intake (kcal; control: 1040 ± 73; L-Val-0.15: 1040 ± 81; L-Val-0.45: 1056 ± 100), at either load (p > 0.05 for all). In conclusion, intraduodenal infusion of L-valine, at loads that are moderately (3.3 g) or substantially (9.9 g) above World Health Organization valine requirement recommendations, does not appear to have energy intake- or blood glucose-lowering effects.

scholarly journals Effects of intragastric administration of L-tryptophan on the glycaemic response to a nutrient drink in men with type 2 diabetes — impacts on gastric emptying, glucoregulatory hormones and glucose absorption

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maryam Hajishafiee ◽  
Rachel A. Elovaris ◽  
Karen L. Jones ◽  
Leonie K. Heilbronn ◽  
Michael Horowitz ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Gastric Emptying ◽  
Plasma Glucose ◽  
Glucose Absorption ◽  
Intragastric Administration ◽  
Glycaemic Response ◽  
C Peptide ◽  
Postprandial Glycaemia ◽  
Glucoregulatory Hormones

Abstract Background The rate of gastric emptying and glucoregulatory hormones are key determinants of postprandial glycaemia. Intragastric administration of L-tryptophan slows gastric emptying and reduces the glycaemic response to a nutrient drink in lean individuals and those with obesity. We investigated whether tryptophan decreases postprandial glycaemia and slows gastric emptying in type 2 diabetes (T2D). Methods Twelve men with T2D (age: 63 ± 2 years, HbA1c: 49.7 ± 2.5 mmol/mol, BMI: 30 ± 1 kg/m2) received, on three separate occasions, 3 g (‘Trp-3’) or 1.5 g (‘Trp-1.5’) tryptophan, or control (0.9% saline), intragastrically, in randomised, double-blind fashion, 30 min before a mixed-nutrient drink (500 kcal, 74 g carbohydrates), containing 3 g 3-O-methyl-D-glucose (3-OMG) to assess glucose absorption. Venous blood samples were obtained at baseline, after tryptophan, and for 2 h post-drink for measurements of plasma glucose, C-peptide, glucagon and 3-OMG. Gastric emptying of the drink was quantified using two-dimensional ultrasound. Results Tryptophan alone stimulated C-peptide (P = 0.002) and glucagon (P = 0.04), but did not affect fasting glucose. In response to the drink, Trp-3 lowered plasma glucose from t = 15–30 min and from t = 30–45 min compared with control and Trp-1.5, respectively (both P < 0.05), with no differences in peak glucose between treatments. Gastric emptying tended to be slower after Trp-3, but not Trp-1.5, than control (P = 0.06). Plasma C-peptide, glucagon and 3-OMG increased on all days, with no major differences between treatments. Conclusions In people with T2D, intragastric administration of 3 g tryptophan modestly slows gastric emptying, associated with a delayed rise, but not an overall lowering of, postprandial glucose.

scholarly journals Effects of branched chain amino acids infusion on whole‐body plasma glucose disposal: a pilot study

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Sarah Everman ◽  
Lawrence J Mandarino ◽  
Guilherme M Puga ◽  
Christian Meyer ◽  
Christos S Katsanos
Keyword(s):  
Amino Acids ◽  
Pilot Study ◽  
Plasma Glucose ◽  
Branched Chain Amino Acids ◽  
Whole Body ◽  
Glucose Disposal ◽  
Branched Chain

scholarly journals Metabolic effects of low cortisol during exercise in humans

1998 ◽  
Vol 84 (3) ◽  
pp. 939-947 ◽  
Author(s):  
Pedro Del Corral ◽  
Edward T. Howley ◽  
Mike Hartsell ◽  
Muhammad Ashraf ◽  
Mary Sue Younger
Keyword(s):  
Amino Acids ◽  
Growth Hormone ◽  
Plasma Glucose ◽  
Respiratory Exchange Ratio ◽  
Branched Chain Amino Acids ◽  
Physiological Effect ◽  
Metabolic Effects ◽  
Whole Body ◽  
Branched Chain ◽  
Exercise In Humans

This study examined the physiological effect of reduced plasma cortisol (C) during prolonged exercise in humans. The effects of normal C (NC) were compared with metyrapone-induced low C (LC) on plasma substrate availability and the respiratory exchange ratio during 2 h of exercise at ∼60% peak O2 consumption in nine subjects. The C responses were compared with preexercise (Pre) levels and with a rest day (Con). At rest, C was attenuated by ∼70% for LC compared with NC. At rest, plasma glucose, lactate, glycerol, β-hydroxybutyrate, alanine, branched-chain amino acids, insulin, glucagon, growth hormone, epinephrine, and norepinephrine were similar under LC and NC ( P > 0.05). During exercise under NC, plasma C increased compared with Pre, whereas it remained unchanged during LC. During NC, plasma C was elevated at 90 min (compared with Con) and at 120 min (compared with Con and Pre). During exercise, plasma glucose decreased to the same extent and lactate was similar under both conditions, whereas plasma glycerol, β-hydroxybutyrate, alanine, and branched-chain amino acids were higher ( P < 0.01) under NC. Plasma insulin declined ( P = 0.01) to a greater extent under LC, whereas growth hormone, epinephrine, and norepinephrine tended to be higher (0.05 ≤ P ≤ 0.10). Plasma glucagon increased under both conditions ( P < 0.01). The respiratory exchange ratio did not differ between conditions. We conclude that, during exercise, 1) C accelerates lipolysis, ketogenesis, and proteolysis; 2) under LC, glucoregulatory hormone adjustments maintain glucose homeostasis; and 3) LC does not alter whole body substrate utilization or the ability to complete 2 h of moderate exercise.

scholarly journals Bolus ingestion of individual branched-chain amino acids alters plasma amino acid profiles in young healthy men

SpringerPlus ◽  
2014 ◽  
Vol 3 (1) ◽  
pp. 35 ◽  
Author(s):  
Takuya Matsumoto ◽  
Koichi Nakamura ◽  
Hideki Matsumoto ◽  
Ryosei Sakai ◽  
Tomomi Kuwahara ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Branched Chain Amino Acids ◽  
Plasma Amino Acid ◽  
Healthy Men ◽  
Amino Acid Profiles ◽  
Branched Chain

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

Nutrients ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2697 ◽  
Author(s):  
Christina McVeay ◽  
Penelope C. E. Fitzgerald ◽  
Michael Horowitz ◽  
Christine Feinle-Bisset
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Insulin Secretion ◽  
Blood Glucose ◽  
Energy Intake ◽  
Lauric Acid ◽  
Fasting Glucose ◽  
Postprandial Blood Glucose ◽  
Saline Control ◽  
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. We have investigated the potential for the combination of C12 and Trp to have additive effects to reduce blood glucose. To address this question, plasma concentrations of glucose, insulin and glucagon were measured in 16 healthy, lean males during duodenal infusions of saline (control), C12 (0.3 kcal/min), Trp (0.1 kcal/min), or C12+Trp (0.4 kcal/min), for 90 min. Both C12 and C12+Trp moderately reduced plasma glucose compared with control (p < 0.05). C12+Trp, but not C12 or Trp, stimulated insulin and increased the insulin-to-glucose ratio (p < 0.05). There was no effect on plasma glucagon. In conclusion, combined intraduodenal administration of C12 and Trp reduced fasting glucose in healthy men, and this decrease was driven primarily by C12. The effects of these nutrients on postprandial blood glucose and elevated fasting blood glucose in type 2 diabetes warrant evaluation.

scholarly journals Effects of supplementation with branched chain amino acids and ornithine aspartate on plasma ammonia and central fatigue during exercise in healthy men

2015 ◽  
Vol 4 ◽  
pp. 377-386 ◽  
Author(s):  
Tomasz Mikulski ◽  
Jan Dabrowski ◽  
Wojciech Hilgier ◽  
Andrzej Ziemba ◽  
Krzysztof Krzeminski
Keyword(s):  
Amino Acids ◽  
Central Fatigue ◽  
Branched Chain Amino Acids ◽  
Plasma Ammonia ◽  
Healthy Men ◽  
Branched Chain
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