Metabolites of the aminoacetone pathway in blood after exercise

The following article reports (A) data on glyoxalase I activity in skeletal muscle of untrained men and endurance—trained athletes, and (B) the presence at rest and the rise in blood after exercise of two metabolites of the aminoacetone pathway of amino acid degradation in man. Glyoxalase I showed an average activity of 191 ± 38 U/g wet weight (37°C) in bioptic samples of m.vastus medialis quadricipitis of young adults whereas this was of 235 ± 64 U/g (p < 0.15) in athletes. After an ergometer exercise test with increasing intensity (50 to 400 Watt (W), 3 min-steps) by well trained cyclists, blood L-(+)-lactate increased to 10.12 mmole/liter, whereas methylglyoxal rose by 48.4% and D-(-)-lactate by 70% (resting levels 92 and 110/μmole/liter, respectively). The possible physiologic significance of the assumed aminoacetone pathway was discussed with respect to muscular activity.