Effects of pyruvate on the metabolism and insulin resistance of obese Zucker rats

Ivy, John L.; Cortez, M. Y.; Chandler, Resa M.; Byrne, Heidi K.; Miller, Robert H.

doi:10.1093/ajcn/59.2.331

Cited by 20 publications

(14 citation statements)

References 21 publications

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“…Further, they are in agreement with findings of Ivy et al (18) who reported that pyruvyl-glycine supplementation increased plasma triacylglycerols in obese Zucker rats. Ivy et al (18) hypothesized that the increase in triacylglycerols was be due to a greater mobilization or decreased clearance of blood lipids in response to consuming the pyruvyl-glycine diet. Although pre-exercise feeding of calcium pyruvate may have only temporarily increased blood lipids, additional research should evaluate this potentially negative side effect of PYR supplementation.…”

Section: Discussionsupporting

confidence: 93%

“…These results contradict previous findings suggesting that pyruvate supplementation (36 to 53 g) decreases total cholesterol and low-density lipo-protein concentrations by 4% and 5%, respectively, in obese hyperlipidemic patients (17). Further, they are in agreement with findings of Ivy et al (18) who reported that pyruvyl-glycine supplementation increased plasma triacylglycerols in obese Zucker rats. Ivy et al (18) hypothesized that the increase in triacylglycerols was be due to a greater mobilization or decreased clearance of blood lipids in response to consuming the pyruvyl-glycine diet.…”

Section: Discussionsupporting

confidence: 54%

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Effects of calcium pyruvate supplementation during training on body composition, exercise capacity, and metabolic responses to exercise

et al. 2005

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Method: Twenty-three untrained females were matched and assigned to ingest in a double blind and randomized manner either 5 g of calcium pyruvate (PYR) or a placebo (PL) twice daily for 30 d while participating in a supervised exercise program. Prior to and following supplementation, subjects had body composition determined via hydrodensiometry; performed a maximal cardiopulmonary exercise test; and performed a 45-min walk test at 70% of pre-training VO 2 max in which fasting pre-and post exercise blood samples determined.Results: No significant differences were observed between groups in energy intake or training volume. Univariate repeated measures ANOVA revealed that subjects in the PYR group gained less weight (PL 1.2 ± 0.3, PYR 0.3 ± 0.3 kg, P = 0.04), lost more fat (PL 1.1 ± 0.5; PYR −0.4 ± 0.5 kg, P = 0.03), and tended to lose a greater percentage of body fat (PL 1.0 ± 0.7; PYR −0.65 ± 0.6%, P = 0.07), with no differences observed in fat-free mass (PL 0.1 ± 0.5; PYR 0.7 ± 0.3 kg, P = 0.29). However, these changes were not significant when body composition data were analyzed by MANOVA (P = 0.16). There was some evidence that PYR may negate some of the beneficial effects of exercise on HDL values. No significant differences were observed between groups in maximal exercise responses or metabolic responses to submaximal walking. Conclusions:Results indicate that PYR supplementation during training does not significantly affect body composition or exercise performance and may negatively affect some blood lipid levels.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionsupporting

confidence: 54%

Effects of calcium pyruvate supplementation during training on body composition, exercise capacity, and metabolic responses to exercise

et al. 2005

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“…throughout the duration of the trial Johnstone et al (1989) found that supplementation of pyruvate/dihydroxyacetone (1 : 1; Pyr/D) to the diet significantly decreased the BW of Single Comb White Leghorn pullets. Cortez et al (1991), and Ivy et al (1994) also showed that Pyr fed for 3 to 5 weeks to rats results in decreased BW. Although Cr and Cr-Pyr reduced ADG and ADFI, BW was not affected in the Cr and Cr-Pyr broilers throughout the length of the trial.…”

Section: Discussionmentioning

confidence: 93%

Comparison of the novel compounds creatine and pyruvateon lipid and protein metabolism in broiler chickens

Chen

Wang

Kong

et al. 2011

Animal

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The effects of pyruvate (Pyr), creatine pyruvate (Cr-Pyr) and creatine (Cr) on lipid and protein metabolism were compared in broiler chickens. A total of 400 1-day-old male birds (Aconred) were allocated to four groups, each of which included four replicates (25 birds per replicate). Treatments consisted of unsupplemented basal diet (Control), basal diet containing 2% Pyr, basal diet containing 3% Cr and basal diet containing 5% Cr-Pyr. Cr-Pyr and Pyr significantly decreased the hepatic triglyceride and serum total cholesterol concentration (P , 0.01). Cr-Pyr markedly increased the serum non-esterified fatty acid and highdensity lipoprotein cholesterol concentrations (P , 0.05), whereas the expression of carnitine palmitoyl transferase I (P , 0.05) and peroxisome proliferators-activated receptor-a (P , 0.01) mRNA in the liver were both decidedly enhanced in the Cr-Pyr group. The relative leg muscle weight was higher in the Cr-Pyr group than in the control group, whereas the serum uric acid content and hepatic glutamic-oxaloacetic transaminase activity were lower in the Cr-Pyr and Cr groups (P , 0.05), respectively. Muscle insulin-like growth factor I (P , 0.05) expression was enhanced, and the myostatin (P , 0.01) mRNA level was reduced in both the Cr-Pyr and Cr groups. In addition, Cr-Pyr did not alter body weight or the feed conversion ratio. These results indicate that, compared with Pyr and Cr alone, Cr-Pyr has a bifunctional role in broiler chickens, in that it influences both lipid and protein metabolism.Keywords: creatine pyruvate, pyruvate, creatine, lipolysis, protein synthesis ImplicationsIn this study, the administration of creatine pyruvate (Cr-Pyr, a new compound, which contains pure pyruvic acid molecularly bound to pure pharmaceutical grade creatine at a concentration ratio of 40 : 60) was compared with the administration of Pyr or Cr alone for its effect on lipid and protein metabolism in broilers. The insights gained from this study will provide a better understanding of the mechanisms involved in the Cr-Pyr effect on broiler chickens. Further clarity will help the industry to avoid obesity-related problems during production and explore new ways to improve muscle growth in broilers.

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“…There is also evidence that the mitochondria of the obese Zucker rat are dysfunctional. For example, these rats have a low metabolic rate and decreased reliance on fat as an energy source at rest and during exercise (6,21,22,52). In addition, the obese Zucker rat has extremely high intramuscular triglyceride content, which suggests that its muscle is incapable of normal fat oxidation (9).…”

Section: Discussionmentioning

confidence: 99%

LKB1-AMPK signaling in muscle from obese insulin-resistant Zucker rats and effects of training

Sriwijitkamol

Ivy

Christ-Roberts

et al. 2006

American Journal of Physiology-Endocrinology and Metabolism

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is a key regulator of fat and carbohydrate metabolism. It has been postulated that defects in AMPK signaling could be responsible for some of the metabolic abnormalities of type 2 diabetes. In this study, we examined whether insulin-resistant obese Zucker rats have abnormalities in the AMPK pathway. We compared AMPK and ACC phosphorylation and the protein content of the upstream AMPK kinase LKB1 and the AMPKregulated transcriptional coactivator PPAR␥ coactivator-1 (PGC-1) in gastrocnemius of sedentary obese Zucker rats and sedentary lean Zucker rats. We also examined whether 7 wk of exercise training on a treadmill reversed abnormalities in the AMPK pathway in obese Zucker rats. In the obese rats, AMPK phosphorylation was reduced by 45% compared with lean rats. Protein expression of the AMPK kinase LKB1 was also reduced in the muscle from obese rats by 43%. In obese rats, phosphorylation of ACC and protein expression of PGC-1␣, two AMPK-regulated proteins, tended to be reduced by 50 (P ϭ 0.07) and 35% (P ϭ 0.1), respectively. There were no differences in AMPK␣1, -␣2, -␤1, -␤2, and -␥3 protein content between lean and obese rats. Training caused a 1.5-fold increase in AMPK␣1 protein content in the obese rats, although there was no effect of training on AMPK phosphorylation and the other AMPK isoforms. Furthermore, training also significantly increased LKB1 and PGC-1␣ protein content 2.8-and 2.5-fold, respectively, in the obese rats. LKB1 protein strongly correlated with hexokinase II activity (r ϭ 0.75, P ϭ 0.001), citrate synthase activity (r ϭ 0.54, P ϭ 0.02), and PGC-1␣ protein content (r ϭ 0.81, P Ͻ 0.001). In summary, obese insulin-resistant rodents have abnormalities in the LKB1-AMPK-PGC-1 pathway in muscle, and these abnormalities can be restored by training.acetyl-CoA carboxylase; peroxisome proliferator-activated receptor-␥ coactivator-1␣; exercise AMP-ACTIVATED PROTEIN KINASE (AMPK) is an energy-sensing enzyme that is activated by increases in AMP-to-ATP ratios through mechanisms involving allosteric modification and phosphorylation by one or more upstream AMPK kinases (AMPKKs) (11,25). AMPK is a heterotrimer that is formed by a catalytic ␣-subunit and the regulatory ␤-and ␥-subunits. There are two isoforms of the ␣-and ␤-subunits and three isoforms of the ␥-subunit (11, 25). Upon activation, AMPK switches on catabolic pathways that generate ATP, such as glucose transport and fatty acid oxidation, coupled with the inhibition of ATP-consuming (anabolic) pathways that include triglyceride and cholesterol synthesis. It has become apparent in recent years that AMPK plays a key role in mediating the acute and long-term effects of exercise on carbohydrate and fat metabolism in skeletal muscle. AMPK mediates, at least in part, exercise-stimulated increases in muscle glucose transport (3,15,34,35) and fatty acid oxidation (53, 57). The stimulatory effect of AMPK on fatty acid oxidation results from the phosphorylation and inhibition of acetyl-CoA carboxylase (ACC) by AMPK (10, 53, 59). There is evidence that AM...

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Effects of pyruvate on the metabolism and insulin resistance of obese Zucker rats

Cited by 20 publications

References 21 publications

Effects of calcium pyruvate supplementation during training on body composition, exercise capacity, and metabolic responses to exercise

Effects of calcium pyruvate supplementation during training on body composition, exercise capacity, and metabolic responses to exercise

Comparison of the novel compounds creatine and pyruvateon lipid and protein metabolism in broiler chickens

LKB1-AMPK signaling in muscle from obese insulin-resistant Zucker rats and effects of training

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