| Summary: | 博士 === 國立體育大學 === 競技與教練科學研究所 === 101 === Anti-estrogenic activity agents are used to reduce serum estrogen levels, and these compounds have been known to increase serum testosterone levels by inhibiting testosterone conversion into estrogen. Anti-estrogenic activity agents are listed as doping substances on the World Anti-Doping Agency (WADA) Prohibited List due to the potential ability for performance enhancement. Due to the increase of adverse analytical findings in this doping class, the WADA regulations are also getting stricter. Hence, the analytical methods of doping have to be improved continuously. In our study, a systemic analytical method of anti-estrogenic activity agents in urine by LC-MS/MS was successfully developed. The established method can be used to detect 9 agents with anti-estrogenic activity in a single run. The LLOD were during 0.5 - 5 ng/mL. This method has good reproducibility, and could be applied for the use of doing screening.
Raloxifene is one of selective estrogen receptor modulators (SERMs) which are included in anti-estrogenic activity agents. Raloxifene is well tolerated and has positive effects on the body mass density of elderly women and the serum testosterone of elderly men. They suggested that raloxifene might have potential to enhance exercise performance. However, raloxifene in urine samples from athletes had never been detected in WADA’s annual analytical results reports until 2011. Therefore, a quantitative method of raloxifene in urine established by modifying the present systemic screening method was applied to investigate the elimination of urinary raloxifene after administering a single oral dose. Referring to the quantitative method of raloxifene, the lower limit of quantification was 0.5 ng/mL. Linearity was observed for raloxifene concentrations ranging from 0.5 to 100 ng/mL with a correlation coefficient of 0.999. The average recovery was 94.82 %. Inaccuracies were below ±5% and precisions varied from 2.18 to 5.78%. Moreover, after taking one single dose of 60 mg raloxifene, the urinary raloxifene was immediately detectable within 4 hours. Furthermore, the urinary raloxifene could be detected till 6 to 10 days later.
We also investigated the impact of raloxifene on gonadal hormones and urinary testosterone/epitestosterone ratio in young men and women. The results indicated that in both men and women, a single dose of raloxifene did not increase serum total testosterone and estradiol concentrations. However, it might reduce the serum free testosterone concentrations, the actual active testosterone which is able to utilize. All data of urinary testosterone/epitestosterone ratio was less than 4 after the administration of a single dose of raloxifene. In conclusion, the administration of only a singly dose of raloxifene could not enhance the sport performance. However, it might violate the WADA rules. We suggest that athletes should not take a risk out of desperation for using doping.
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