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 degrees 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 100/mumole/liter, respectively). The possible physiologic significance of the assumed aminoacetone pathway was discussed with respect to muscular activity.