ABSTRACT
According to the World Anti-Doping Agency (WADA) Prohibited List both S1 and S2 classes of doping agents are comprised of by and large naturally occurring hormones and their synthetic derivatives. The S4 class entitled, ‘Hormone and Metabolic Modulators’ contains several groups of synthetic compounds, or otherwise, which act by modulating various endogenous hormonal pathways and local muscle-specific transduction pathways. The aim of such modulators is in most cases to enhance exercise performance, however in the case of aromatase inhibitors, selective oestrogen receptor modulators (SERMs) or other anti-oestrogenic substances, it may be to counteract the unwanted side effects of anabolic androgenic steroid administration. Androgens are readily converted to oestrogens by the enzyme aromatase. Aromatase inhibitors are therefore a class of drugs that limit this conversion by binding to aromatase and rendering it inactive. SERMs are attractive anti-oestrogen drugs since they target specific tissues without affecting other organs.
