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 af ter strong exercise, which exhausted the subjects, the ratio of tetrah ydrobiopterin to total biopterin not differing before and after exerci se. The increase of plasma biopterins disappeared 2 h after exercise. The mechanism of the increase of plasma biopterins was thought to be d ifferent from that of patients with affective disorders.