Ostarine is a non-steroidal agent with anabolic activity. Selective androgen receptor modulator (SARM) GTx-024 is designed to work like testosterone, thus promoting and/or maintaining libido, fertility, prostate growth, and muscle growth and strength. Mimicking testosterone's action, this agent may increase lean body mass, thereby ameliorating muscle wasting in the hypermetabolic state of cancer cachexia[1].
Ostarine has been used in trials studying the treatment of Stress Urinary Incontinence and Triple Negative Breast Cancer.
Fig 1. Chemical structure formula and three-dimensional structure of Ostarine
Ostarine is a selective androgen receptor modulator (SARM) with Ki of 3.8 nM. Plasma concentration of ostarine declines in a biexponential manner after intravenous administration with terminal half-live of 6.0 hours. In vivo, ostarine significantly stimulates the growth of prostate, seminal vesicles, and levator ani muscle in castrated rats. Ostarine restores the weights of the prostate to 39.2%, of that observed in the intact control. The weight of seminal vesicle is also restored by ostarine to 78.8%, respectively, of that observed in the intact control. Ostarine stimulates the growth of levator ani muscle to a greater extent than androgenic organs, to 141.9%. Nonlinear regression analysis of dose-response relationships for ostarine shows that the ED50 values are 0.12, 0.39, and 0.03 mg/day in prostate, seminal vesicles, and levator ani muscle, respectively. Ostarine maximally restores the weights of prostate, seminal vesicles, and levator ani muscle to 51.1, 98.0, and 136.3, respectively, of that the intact control. Ostarine exerts efficacious and selective activity in anabolic tissues at dose rates as low as 0.03 mg/day, indicative of the high potency of ostarine in anabolic tissue. Ostarine demonstrates the greatest in vivo androgenic and anabolic activity of any androgen receptor (AR) nonsteroidal agonist examined to date and exceeds the anabolic activity of testosterone propionate[2].
Ostarine (MK-2866) is a selective androgen receptor modulator (SARM) with anabolic activity. Ostarine (MK-2866) also resulted in a dose-dependent decrease in LDL and HDL cholesterol levels, with the average LDL/HDL ratio remaining in the low risk category. Ostarine exhibits significantly androgenic and anabolic activity by stimulating the growth of prostate, seminal vesicles, and levator ani muscle when administered in castrated male rats. Ostarine is more potent than other cyano/nitro group-substituted SARMs. Ostarine exhibits the highest in vivo androgenic and anabolic activity of any AR nonsteroidal agonist examined to date, with ED50 values of 0.12, 0.39 and 0.03 mg/day in prostate, seminal vesicles, and levator ani muscle, respectively[3,4].
References
[1]Dalton JT, Barnette KG, Bohl CE, Hancock ML, Rodriguez D, Dodson ST, Morton RA, Steiner MS. The selective androgen receptor modulator GTx-024 (enobosarm) improves lean body mass and physical function in healthy elderly men and postmenopausal women: results of a double-blind, placebo-controlled phase II trial. J Cachexia Sarcopenia Muscle. 2011 Sep;2(3):153-161.
[2]Kim J, et al. The para substituent of S-3-(phenoxy)-2-hydroxy-2-methyl-N-(4- nitro-3-trifluoromethyl-phenyl)-propionamides is a major structural determinant of in vivo disposition and activity of selective androgen receptor modulators. J Pharmacol Exp Ther. 2005, 315(1): 230-239.
[3]Recent advances in the development of selective androgen receptor modulators.Zhang X, et al. Expert Opin Ther Pat. 2009 Sep;19(9):1239-58.
[4]Nonsteroidal selective androgen receptor modulators (SARMs): dissociating the anabolic and androgenic activities of the androgen receptor for therapeutic benefit.Mohler ML, et al. J Med Chem. 2009 Jun 25;52(12):3597-617.