Androgen turnover during marathon running.

The purpose of the study was to investigate the effect of prolonged physical stress on peripheral androgen turnover. Venous blood samples were taken from 18 athletes 24 h before finishing a competitive marathon run and directly after running the race. Serum cortisol, testosterone (T), dehydroepiandrosteronesulfate (DHEAS), sex hormone binding globulin (SHBG), and 5 alpha-androstane- 3 alpha, 17 beta-diolglucuronide (3 alpha-AdiolG) were determined and corrected for hemoconcentration. Marathon running caused a rise in serum cortisol concentration in all athletes. Furthermore, a significant (P < 0.01) rise in serum T and T-index (index of free T) was observed. The significant (P < 0.01) rise in serum DHEAS concentration, a mainly adrenal cortical androgen, pointed toward a stimulation of the adrenal cortex or a reduced hepatic metabolic clearance rate. Finally, 3 alpha-AdiolG, an androgen metabolite exclusively formed in peripheral tissues, was increased in the sera of all athletes. These results suggest that marathon running leads to increased concentrations of serum adrenal and gonadal androgens. The simultaneously increased 3 alpha-AdiolG levels may be caused by increased androgen turnover in peripheral tissues containing 5 alpha-reductase.