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Leonardo F. Ferreira, Kenneth S. Campbell, and Michael B. Reid

N-acetylcysteine (NAC) is a thiol donor with antioxidant properties that has potential use as an ergogenic aid. However, NAC is associated with adverse reactions that limit its use in humans.


The authors evaluated NAC efficacy as a thiol donor before handgrip exercise, measuring changes in serum cysteine and glutathione status and recording adverse reactions in adult subjects across a range of doses.


Healthy individuals ingested NAC capsules (9 ± 2 or 18 ± 4 mg/kg) or solution (0, 35, 70, or 140 mg/kg). Venous blood samples were collected and subjects answered a questionnaire about adverse reactions.


Low doses of NAC (capsules) did not affect plasma cysteine or glutathione or cause adverse reactions. Adverse reactions to NAC solution were predominantly mild and gastrointestinal (GI). Intensity of GI reactions to 140 mg/kg NAC was significantly higher than placebo (in a.u., 0.67 ± 0.16 vs. 0.07 ± 0.04; p < .05). Plasma cysteine concentration increased with NAC dose from 9.3 ± 0.7 μM (placebo) to 65.3 ± 6.7 μM (140 mg/kg); however, there was no difference (p > .05) in plasma cysteine for 70 mg/kg vs. 140 mg/kg. Similar increases were observed for the ratio of cysteine to total cysteine, which was directly related to handgrip exercise performance. Plasma glutathione was elevated and oxidized glutathione diminished (p < .05) with NAC 140 mg/kg vs. placebo.


NAC effects on plasma thiols are maximized by oral administration of 70 mg/kg, a dose that does not cause significant adverse reactions.

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Theodore Tsakiris, Panagoula Angelogianni, Christine Tesseromatis, Stylianos Tsakiris, and Kleopatra H. Schulpis


Forced exercise is associated with oxidative stress, and L-cysteine (L-cys) administration reduces free-radical production.


To investigate whether L-cys (5 mg/kg) intraperitoneal administration can ameliorate modulated total antioxidant status (TAS), protein concentration, and the activities of acetylcholinesterase (AChE), (Na+,K+)-ATPase, and Mg2+-ATPase in rat brain after 2 and 3 hr of forced swimming.


TAS, protein, and enzyme activities were measured spectrophotometrically before and after 2 and 3 hr of exercise without or with L-cys administration.


TAS concentration (55.6 ± 1.5 vs. 42.1 ± 1.0 vs. 37.4 ± 1.2 μmol/L, p < .001), protein concentration (5.68 ± 0.36 vs. 5.40 ± 0.18 vs. 4.01 ± 0.16 mg/ml, p < .01), and AChE activity (0.89 ± 0.05 vs. 0.61 ± 0.04 vs. 0.48 ± 0.03 ΔOD/min × mg protein, p < .001) were significantly reduced, whereas Na+,K+-ATPase (6.00 ± 0.36 vs. 10.44 ± 1.04 vs. 11.90 ± 1.21 µmol phosphorus inorganic/hr × mg protein, p < .001) and Mg2+-ATPase activity (7.20 ± 0.65 vs. 10.88 ± 1.08 vs. 11.55 ± 1.22 µmol phosphorus inorganic/hr × mg protein, p < .001) were statistically significantly increased after 2 and 3 hr of forced exercise. Post-L-cys administration, AChE activity was decreased (0.90 ± 0.04 vs. 0.47 ± 0.02 ΔOD/min × mg protein, p < .001) and remained unaltered (0.64 ± 0.04 vs. 0.67 ± 0.04 ΔOD/min × mg protein, p > .05) 2 and 3 hr postexercise (0.47 ± 0.02 vs. 0.54 ± 0.02 ΔOD/min × mg protein, p > .05). Na+,K+-ATPase was decreased and remained unchanged (1.85 ± 0.17 vs. 1.77 ± 0.19 µmol phosphorus inorganic/hr × mg protein, p > .05) 2 and 3 hr postswimming (1.91 ± 0.19 vs. 2.06 ±0.17 µmol phosphorus inorganic/hr × mg protein, p > .05). Mg2+-ATPase activity was similar with L-cys supplementation pre- vs. postswimming.


L-cys administration might ameliorate modulated rat brain enzyme activities induced by free-radical production during forced swimming.

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G.W. Davison, C.M. Hughes, and R.A. Bell

The purpose of this investigation was to determine the effects of antioxidant supplementation on DNA damage following exercise. Fourteen subjects were randomly assigned to one of two groups and required to ingest either antioxidants (400 mg α-lipoic acid, 200 mg co-enzyme Q10, 12 mg manganese, 600 mg vitamin C, 800 mg N-acetyl cysteine, 400 μg selenium, and 400 IU α-tocopherol per day) or placebos for 7 d. Exercise increased DNA damage, PS, FRAP, and LDH (P < 0.05), but not selectively between groups. LDH and PS concentration decreased 1 h post-exercise (P < 0.05), while LH concentration decreased 1 h post-exercise in the antioxidant group only (P < 0.05). The antioxidant group had a higher concentration of LH (P < 0.05), perhaps due to a selective difference between groups post-exercise (P < 0.05). The main findings of this investigation demonstrate that exhaustive aerobic exercise induces DNA damage, while anti-oxidant supplementation does not protect against damage.

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Gustavo Monnerat, Carlos A.R. Sánchez, Caleb G.M. Santos, Dailson Paulucio, Rodolfo Velasque, Geisa P.C. Evaristo, Joseph A.M. Evaristo, Fabio C.S. Nogueira, Gilberto B. Domont, Mauricio Serrato, Antonio S. Lima, David Bishop, Antonio C. Campos de Carvalho, and Fernando A.M.S. Pompeu

, 39 was found increased in the group with higher V ˙ O 2 max after maximal exercise test when compared with individuals with lower V ˙ O 2 max . Methionine is an essential amino acid that acts a precursor for different important molecules, such as cysteine and taurine. Besides, methionine is a key

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Nathan A. Lewis, Ann Redgrave, Mark Homer, Richard Burden, Wendy Martinson, Brian Moore, and Charles R. Pedlar

. Effect of supplementation with a cysteine donor on muscular performance . J Appl Physiol . 1999 ; 87 : 1381 – 1385 . PubMed 10.1152/jappl.1999.87.4.1381 10517767 16. Bell PG , Walshe IH , Davison GW , et al . Montmorency cherries reduce the oxidative stress and inflammatory responses to

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André L. Estrela, Aline Zaparte, Jeferson D. da Silva, José Cláudio Moreira, James E. Turner, and Moisés E. Bauer

cysteine, homocysteine, reduced glutathione, cyteinylglycine or albumin, will be detected ( Biswas, Chida, & Rahman, 2006 ; Giustarini, Dalle-Donne, Lorenzini, Milzani, & Rossi, 2006 ; Rossi, Giustarini, Milzani, & Dalle-Donne, 2009 ). However, considering only reduced thiolsare detected by this assay

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Dana M. Lis and Keith Baar

aminoethylation-cysteine buffer, and a 50-μl injection volume was analyzed using a high-speed Amino Acid Analyzer (model L-8900; Hitachi High-Technologies, Pleasanton, CA). Statistical Analysis Sample size calculations for the study were based on the mean changes in PINP and SD s established in previous work in

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Fernando Naclerio, Eneko Larumbe-Zabala, Mar Larrosa, Aitor Centeno, Jonathan Esteve-Lanao, and Diego Moreno-Pérez

(24 g of Powder  + 250 ml of Orange Juice) Nutrient CHO + PRO CHO Energy value (kcal) 204 204 Carbohydrates (g) 27.70 50.10 Lipids (g) 1.05 0 Proteins (g) 19.84 0.40 Alanine (g) 1.14 – Arginine (g) 0.82 – Aspartic acid (g) 1.94 – Cysteine (g) 0.33 – Glutamic acid (g) 3.33 – Glycine (g) 0

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Matthew J. McAllister, Joni A. Mettler, Kyle Patek, Matthew Butawan, and Richard J. Bloomer

production of GSH using endogenous amino acids glutamate, cysteine, and glycine, while the resynthesis pathway recycles GSH from oxidized GSH via enzyme GSH reductase and nicotinamide adenine dinucleotide phosphate (NADPH) ( Townsend et al., 2003 ). Since ASTA may activate the Nrf2 pathway, it is possible

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Henning T. Langer, Agata A. Mossakowski, Suraj Pathak, Mark Mascal, and Keith Baar

/EBP-homologous protein (CHOP) (#5554); Santa Cruz (Santa Cruz Biotechnology Inc., Dallas, TX): Dystrophin (#365954; lot E2711), Dysferlin (#16635; lot H162), Desmin (#271677; lot F1913), muscle LIM protein (mLIM)/cysteine and glycine-rich protein 3 (mLIM) (#166930; lot E2814); Millipore Sigma (Merck Group): insulin