[Testicular secretions of androgens after prolonged physical effort in man]

Variations in plasma testosterone, dihydrotestosterone. delta 4 androstenedione, LH, FSH and cortisol were measured before and after 6 succesive effort tests in 11 male subjects. Testicular secretion and the extra-hepatic consumption of androgens are increased by the haemodynamic conditions of effort but plasma levels of testosterone and dihydrotestosterone fall with repeated effort, indicating a progressive imbalance between production and consumption. These variations suggest that the testis, rather than glucocorticoid function of the adrenal, might play a major limiting role, psychological and metabolic, in tolerance of prolonged effort.