title: Acute variations in homocysteine levels are related to creatine changes induced by physical activity.
abstract: OBJECTIVE
  Although many studies have focused on the effects of the physical activity on plasma homocysteine (Hcy) levels, the data gathered up to now are contradictory. In fact, it is true that some researches highlighted an exercise-induced fall in Hcy concentrations, but there are many reports proving that the physical exercise does not contribute to depress plasma Hcy levels and/or that in some instances it would even produce an increase. As a result, the question about the nature of the relationship between Hcy and physical activity remains unanswered. In this study, we have investigated whether the modification in Hcy level after a moderate physical activity was explainable in the light of the common connection of physical activity and Hcy to creatine (Cn).
  
  
  METHODS
  In 16 young volunteers aged from 21 to 37, divided into sedentary (n=6) and athletes (n=10) sub-groups, before and after an incremental cycle ergometer stress test, performed every 30 days for 4 months, we measured the plasma levels of guanidino acetic acid (GAA), ornithine (Orn), glycine (Gly), arginine (Arg), methionine (Met) as well as the plasma levels of Cn and of total and reduced form of the homocysteine (tHcy, rHcy). By difference in the total proteins (tProt) amount between the pre- and post-exercise phases also the dehydration degree of the subjects was measured.
  
  
  RESULTS
  After exercise rHcy decreased, tHcy was unchanged while Cn increased. Gly, Arg and Met at the end of exercise remained unaffected whereas, interestingly, GAA decreased in both sub-groups while Orn was significant diminished in athletes and, although not significantly, the same trend was observable in the sedentaries group.
  
  
  CONCLUSIONS
  These findings support an interesting hypothesis on the key role of the creatine haemoconcentration as an important modality by which physical exercise would affect plasma Hcy levels.
authors.affiliation: Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/B-I-07100, Sassari, Italy. salvatore.sotgia@gmail.com
authors.forename: Salvatore
authors.initials: S
authors.lastname: Sotgia
authors.forename: Ciriaco
authors.initials: C
authors.lastname: Carru
authors.forename: Marcello A
authors.initials: MA
authors.lastname: Caria
authors.forename: Bruna
authors.initials: B
authors.lastname: Tadolini
authors.forename: Luca
authors.initials: L
authors.lastname: Deiana
authors.forename: Angelo
authors.initials: A
authors.lastname: Zinellu
mesh_terms: D000328:Adult; D001120:Arginine / Q000097:blood / Q000378:metabolism; D003401:Creatine / Q000097:blood* / Q000378:metabolism; D005080:Exercise Test; D005998:Glycine / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism; D006710:Homocysteine / Q000097:blood* / Q000378:metabolism; D006801:Humans; D008297:Male; D008715:Methionine / Q000097:blood / Q000378:metabolism; D009952:Ornithine / Q000097:blood / Q000378:metabolism; D005082:Physical Exertion / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*
chemical_list: D006710:Homocysteine; D001120:Arginine; D008715:Methionine; D009952:Ornithine; C004946:glycocyamine; D003401:Creatine; D005998:Glycine