Description:
IC50 Value: 6.6 nM [1]
MK-0773, one of Selective androgen receptor modulators (SARMs), is a 4-aza-steroid that exhibited tissue selectivity in humans.
in vitro:  The IC50 of MK-0773 binding to AR was increased 3.5-fold in the presence of 25% rat serum and 13-fold in the presence of 25% human serum, indicating that it binds to serum proteins. The affinity of MK-0773 for AR across species was evaluated using COS cells transfected with AR, and IC50 values were very similar in four species (rat, 0.50 nM; dog, 0.55 nM; rhesus, 0.45 nM; human, 0.65 nM) [1].
in vivo: MK-0773 was dosed subcutaneously for 24 days in the OVX rat model (6 and 80 mg/kg) and produced plasma exposures over 24 h of 6.6 and 62 μM·h. This treatment produced exposure-related stimulatory effects on cortical BFR and LBM. The maximal anabolic effects of MK-0773 were equivalent to the SARM TFM-4AS-1 and ?80% of 3 mg/kg DHT [1]. Participants receiving MK-0773 showed a statistically significant increase in LBM from baseline at Month 6 vs. placebo (p<0.001). Participants receiving both MK-0773 and placebo showed a statistically significant increase in strength from baseline to Month 6, but the mean difference between the two groups was not significant (p=0.269) [2].
Clinical trial: Safety, Tolerability and Efficacy of MK-0773 in Healthy Postmenopausal Women. Phase 1