title: Effects of two training protocols on Angiotensin I-converting enzyme (ACE) activity in horses.
abstract: BACKGROUND
  Studies in man have shown a correlation between Angiotensin I-converting enzyme (ACE) genetic polymorphisms, ACE activity in the blood and superior athletic performance in sports requiring endurance. It has been hypothesised that the same correlation occurs in horses. There is no information in the literature concerning the effects of training on ACE activity in equine plasma.
  
  
  OBJECTIVE
  Exercise training influences the activity of circulating ACE and the response observed is dependent on the exercise protocol.
  
  
  METHODS
  Thirteen horses of mixed breeds were randomly allocated 2 different training protocols to be carried out for a period of 15 weeks. Blood samples were collected from each horse before the beginning of training to determine baseline values. Subsequent sampling took place every 15 days throughout the training phase and for 8 weeks of paddock rest. Angiotensin I-converting enzyme activity was determined by automated spectrophotometry.
  
  
  RESULTS
  Training for 15 weeks significantly increased plasma ACE activity, irrespective of training protocol. Differences observed in ACE activity pattern between the 2 training protocols were not statistically significant. Increase in ACE activity peaked with maximum workload. As soon as training was interrupted, ACE levels significantly decreased.
  
  
  CONCLUSIONS
  Exercise training affects levels of ACE activity in equine plasma. The mechanism for this is not yet elucidated, but cardiovascular adaptation to exercise and blood pressure changes might be involved in this regulation.
  
  
  CONCLUSIONS
  Exercise training produced a gradual increase in enzymatic activity and might warrant the use of ACE as a tool for fitness monitoring. Angiotensin I-converting enzyme enzymatic activity in the plasma might be directly correlated to a change in genetic expression and that variability must be taken into account when evaluating results from horses undergoing a physical training programme.
authors.affiliation: Waikato Institute of Technology, Department of Science and Primary Industries, Hamilton, New Zealand. mfveterinaria@hotmail.com
authors.forename: M F M
authors.initials: MF
authors.lastname: Costa
authors.forename: H M
authors.initials: HM
authors.lastname: Davies
authors.forename: G A
authors.initials: GA
authors.lastname: Anderson
authors.forename: R F
authors.initials: RF
authors.lastname: Slocombe
mesh_terms: D000818:Animals; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006736:Horses / Q000097:blood / Q000502:physiology*; D008297:Male; D007703:Peptidyl-Dipeptidase A / Q000097:blood*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D011897:Random Allocation
chemical_list: D007703:Peptidyl-Dipeptidase A