Disposition of urinary and serum steroid metabolites in response to testosterone administration in healthy women.

CONTEXT Little is known about how exogenous testosterone (T) affects the steroid profile in women. More knowledge would give the anti-doping community keys on how to interpret tests and detect doping. OBJECTIVE To investigate the steroid profile in serum and urine in young healthy women after testosterone administration. METHODS In a randomized, double-blind, placebo-controlled study, 48 healthy young women, were assigned to treatment with T cream (10 mg) or placebo (1:1) for 10 weeks. Urine and blood were collected before and at end of treatment. Serum steroids were analyzed with LC-MS/MS, and urine levels of T, epitestosterone (E) and metabolites included in the Athlete Biological Passport (ABP) were analyzed with GC-MS/MS. RESULTS In serum, T and dihydrotestosterone levels increased, whereas sex-hormone-binding globulin and 17-hydroxyprogesterone decreased after T treatment as compared to placebo. In urine, T and 5α-androstanediol increased in the T group. The median T increase in serum was 5.0-fold (range 1.2-18.2) and correlated to a 2.2-fold (range 0.4-14.4) median increase in T/E in urine (rs=0.76). Only two of the 24 women receiving T reached the T/E cut-off ratio of 4, while when the results were added to the ABP, six of 15 subjects showed atypically high T/E (40%). In comparison, 22/24 women in the T group increased serum T more than 99.9% of the upper confidence limit of non-treated values. CONCLUSION It seems as T/E ratio is not sufficient to detect exogenous testosterone in women. Serum total T concentrations could serve as a complementary marker of doping.