Enobosarm in Muscle Wasting

Testosterone is an important anabolic in humans, but its conversion to dihydrotestosterone in skin and prostate and to oestradiol in adipose tissue also yields untoward androgenic and estrogenic effects.It was therefore a breakthrough of considerable interest, when Dalton and colleagues in 1998 reported the synthesis of non-steroidal arylpropionamide ligands for the androgen receptor.Three of these newly discovered ligands bound the receptor with affinity similar to dihydrotestosterone and mimicked its effects on receptor-mediated transcriptional activation, thus demonstrating agonist activity [1].Since then, a number of different non-steroidal chemical scaffolds have been developed to mimic androgen receptor ligands, including bicyclic hydantoins, bicyclic thiohydantoins, imidazolopyrazoles, benzimidazoles, anilines and quinolinones.The umbrella term for these substances is selective androgen-receptor modulators (SARMs), and they were developed with the aim of preserving anabolic effects in muscle and bone while reducing androgenic side effects (e.g., prostate stimulation, virilization and gynecomastia) and other safety concerns [2].