Effects of GLP-1 Infusion Upon Whole-body Glucose Uptake and Skeletal Muscle Perfusion During Fed-state in Older Men.

Introduction: Ageing skeletal muscles become both insulin resistant and atrophic. The hormone glucagon-like peptide 1 (GLP-1) facilitates postprandial glucose uptake as well as augmenting muscle perfusion, independent of insulin action. We thus hypothesized exogenous GLP-1 infusions would enhance muscle perfusion and positively affect glucose metabolism during fed-state clamps in older people.

Glucagon-like peptide 1 infusions overcome anabolic resistance to feeding in older human muscle.

Background: Despite its known insulin-independent effects, glucagon-like peptide-1 (GLP-1) role in muscle protein turnover has not been explored under fed-state conditions or in the context of older age, when declines in insulin sensitivity and protein anabolism, as well as losses of muscle mass and function, occur.

Methods: Eight older-aged men (71 ± 1 year, mean ± SEM) were studied in a crossover trial. Baseline measures were taken over 3 hr, prior to a 3 hr postprandial insulin (~30 mIU ml ) and glucose (7-7.

The effect of acute oral phosphatidic acid ingestion on myofibrillar protein synthesis and intracellular signaling in older males.

Background: Age-related muscle loss (sarcopenia) may be driven by a diminished myofibrillar protein synthesis (MyoPS) response to anabolic stimuli (i.e. exercise and nutrition).

Effects of leucine-enriched essential amino acid and whey protein bolus dosing upon skeletal muscle protein synthesis at rest and after exercise in older women.

Background & Aims: Impaired anabolic responses to nutrition and exercise contribute to loss of skeletal muscle mass with ageing (sarcopenia). Here, we tested responses of muscle protein synthesis (MPS), in the under represented group of older women, to leucine-enriched essential amino acids (EAA) in comparison to a large bolus of whey protein (WP).

Methods: Twenty-four older women (65 ± 1 y) received (N = 8/group) 1.

Fuel for the work required: a practical approach to amalgamating train-low paradigms for endurance athletes.

Using an amalgamation of previously studied "train-low" paradigms, we tested the effects of reduced carbohydrate (CHO) but high leucine availability on cell-signaling responses associated with exercise-induced regulation of mitochondrial biogenesis and muscle protein synthesis (MPS). In a repeated-measures crossover design, 11 males completed an exhaustive cycling protocol with high CHO availability before, during, and after exercise (HIGH) or alternatively, low CHO but high protein (leucine enriched) availability (LOW + LEU). Muscle glycogen was different (P < 0.

Acute cocoa flavanol supplementation improves muscle macro- and microvascular but not anabolic responses to amino acids in older men.

The anabolic effects of nutrition on skeletal muscle may depend on adequate skeletal muscle perfusion, which is impaired in older people. Cocoa flavanols have been shown to improve flow-mediated dilation, an established measure of endothelial function. However, their effect on muscle microvascular blood flow is currently unknown.

The effects of resistance exercise training on macro- and micro-circulatory responses to feeding and skeletal muscle protein anabolism in older men.

Key Points: Increases in limb blood flow in response to nutrition are reduced in older age. Muscle microvascular blood flow (MBF) in response to nutrition is also reduced with advancing age and this may contribute to age-related 'anabolic resistance'. Resistance exercise training (RET) can rejuvenate limb blood flow responses to nutrition in older individuals.

Intake of low-dose leucine-rich essential amino acids stimulates muscle anabolism equivalently to bolus whey protein in older women at rest and after exercise.

Dysregulated anabolic responses to nutrition/exercise may contribute to sarcopenia; however, these characteristics are poorly defined in female populations. We determined the effects of two feeding regimes in older women (66 ± 2.5 yr; n = 8/group): bolus whey protein (WP-20 g) or novel low-dose leucine-enriched essential amino acids (EAA) [LEAA; 3 g (40% leucine)].

Leucine-enriched protein feeding does not impair exercise-induced free fatty acid availability and lipid oxidation: beneficial implications for training in carbohydrate-restricted states.

Given that the enhanced oxidative adaptations observed when training in carbohydrate (CHO)-restricted states is potentially regulated through free fatty acid (FFA)-mediated signalling and that leucine-rich protein elevates muscle protein synthesis, the present study aimed to test the hypothesis that leucine-enriched protein feeding enhances circulating leucine concentration but does not impair FFA availability or whole body lipid oxidation during exercise. Nine males cycled for 2 h at 70% VO2peak when fasted (PLACEBO) or having consumed a whey protein solution (WHEY) or a leucine-enriched whey protein gel (GEL), administered as 22 g 1 h pre-exercise, 11 g/h during and 22 g 30 min post-exercise. Total leucine administration was 14.

Pharmacological enhancement of leg and muscle microvascular blood flow does not augment anabolic responses in skeletal muscle of young men under fed conditions.

Skeletal muscle anabolism associated with postprandial plasma aminoacidemia and insulinemia is contingent upon amino acids (AA) and insulin crossing the microcirculation-myocyte interface. In this study, we hypothesized that increasing muscle microvascular blood volume (flow) would enhance fed-state anabolic responses in muscle protein turnover. We studied 10 young men (23.

Naloxone as part of a prolonged release oxycodone/naloxone combination reduces oxycodone-induced slowing of gastrointestinal transit in healthy volunteers.

Objectives: This exploratory study in healthy volunteers investigated the effect of single doses of oxycodone on gastrointestinal (GI) transit time and the degree to which a single dose of naloxone reverses the oxycodone-induced effect.

Methods: Fifteen healthy male volunteers received: oxycodone 10 and2 0 mg, oxycodone/naloxone 10/5 and 20/10 mg (all as prolonged release tablets) and placebo. Each dose was radiolabelled and administered with a capsule containing radiolabelled resin (surrogate for GI contents).

Toxigenic Helicobacter pylori infection precedes gastric hypochlorhydria in cancer relatives, and H. pylori virulence evolves in these families.

Purpose: Helicobacter pylori infection by virulent strains is associated with gastric adenocarcinoma. We aimed to determine whether infection with virulent H. pylori preceded precancerous gastric hypochlorhydria and atrophy in gastric cancer relatives and quantify the extent of virulence factor evolution.

Determinants and consequences of different levels of CagA phosphorylation for clinical isolates of Helicobacter pylori.

Background & Aims: The Helicobacter pylori cag pathogenicity island encodes a secretory system that translocates CagA into epithelial cells, where it becomes tyrosine phosphorylated and induces cytoskeletal rearrangements. Strains with more CagA tyrosine phosphorylation motifs are most closely associated with gastric cancer. Here we assess whether clinical strains can deliver CagA, whether strains with different numbers of CagA phosphorylation motifs have CagA phosphorylated to different degrees, and whether this induces different amounts of epithelial cytoskeletal change.