title: Protein modification responds to exercise intensity and antioxidant supplementation.
abstract: OBJECTIVE
  To assess the effects of different exercise intensities and antioxidant supplementation on plasma protein modification.
  
  
  METHODS
  Trained men (n = 41) from a homogenous population were randomly assigned to perform cycle ergometer exercise either at 70% or 80% of individual .VO2max. Each intensity group was randomly assigned to receive either juice powder concentrate (JPC 70%, n = 11; JPC 80%, n = 10) or placebo (Plac 70%, n = 10; Plac 80%, n = 10) capsules for 28 wk. Four controlled exercise bouts and blood collections were conducted at baseline and study weeks 4, 16, and 28. Blood samples were drawn before (BE), immediately after (IE), and 30 min (30M) and 30 h (30H) postexercise. These samples were analyzed to estimate concentrations of carbonyl groups on plasma proteins (CP) and the redox state of human serum albumin (HSA).
  
  
  RESULTS
  In the Plac group, CP concentrations increased at 80% of .VO2max IE and 30M, returning to preexercise concentrations by 30H (P < 0.05). At both 16 and 28 wk, the Plac groups had significantly higher BE and 30H CP concentrations than the JPC groups (P < 0.05). The reduced fraction of HSA, human mercaptalbumin (HMA), decreased at all four exercise tests at both exercise intensities IE and 30M, returning to preexercise values by 30H (P < 0.05). Supplementation had no influence on HSA.
  
  
  CONCLUSIONS
  These results indicate that CP concentrations increase with 80% .VO2max intensity. The JPC group had lower baseline CP levels after 16 and 28 wk and no exercise-induced CP increase. HSA is reversibly shifted to a more oxidized state by recent intense exercise.
authors.affiliation: Institute of Physiological Chemistry, Medical University of Graz, Harrachgasse 21/II, Medical University of Graz, Graz, Austria. manfred.lamprecht@meduni-graz.at
authors.forename: Manfred
authors.initials: M
authors.lastname: Lamprecht
authors.forename: Karl
authors.initials: K
authors.lastname: Oettl
authors.forename: Guenther
authors.initials: G
authors.lastname: Schwaberger
authors.forename: Peter
authors.initials: P
authors.lastname: Hofmann
authors.forename: Joachim F
authors.initials: JF
authors.lastname: Greilberger
mesh_terms: D000975:Antioxidants / Q000008:administration & dosage / Q000627:therapeutic use*; D019587:Dietary Supplements; D004311:Double-Blind Method; D016552:Ergometry; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction; D009752:Nutritional Status; D018384:Oxidative Stress; D010101:Oxygen Consumption / Q000502:physiology*; D014176:Protein Biosynthesis / Q000502:physiology*; D012709:Serum Albumin
chemical_list: D000975:Antioxidants; D012709:Serum Albumin; C001702:mercaptoalbumin