Serum Alanine During Long-Lasting Physical Exercise

Abstract

To observe the influence of long-lasting exercise on serum alanine levels in men, 87 male athletes (eight running competitions) were examined for exercise-induced changes in serum alanine, α-aminonitrogen, urea, and total serum protein. A correlation between serum alanine values and the exertion time could be demonstrated; there were significant increases in serum alanine up to 80 min, significant decreases after a time longer than 170 min, and an asymtotically approached base value after 300 min. There were strong linear correlations between the exercise-induced changes in serum alanine and those of α-aminonitrogen as well as between the changes in serum alanine and those of serum urea.

In addition, serum alanine was determined in 75 healthy resting adults after an overnight fast. No sex-dependent differences could be found between the values in the 25 untrained males and the 25 untrained females examined; values were also identical for both untrained and trained subjects. The facts observed indicate the role of alanine in organ metabolism during exhaustive endurance exercise.