The effect of exercise on plasma biopterin levels.

The plasma total biopterin and tetrahydrobiopterin levels of 29 normal volunteers were measured before and after exercise by ergometer, and those of 10 were also measured until 24 h after exercise. An increase of plasma total biopterin and tetrahydrobiopterin was observed only after strong exercise, which exhausted the subjects, the ratio of tetrahydrobiopterin to total biopterin not differing before and after exercise. The increase of plasma biopterins disappeared 2 h after exercise. The mechanism of the increase of plasma biopterins was thought to be different from that of patients with affective disorders.