AG 045572 is a potent GnRH receptor antagonist that inhibits the GnRH receptor in humans and rats with Ki values of 6.0 nM and 3.8 nM, respectively.AG 045572 is metabolized by CYP3A and inhibits testosterone.

GnRHR (human):6.0 nM(ki), GnRHR (rat):3.8 nM(ki)

AG 045572 (10 μM, 40 min, for human liver microsomes; 10 μM, 10 min, for male rat liver microsomes; 1 μM, 10 min, for female rat liver microsomes) is metabolized by CYP3A in both rats and humans. The Km values in male and female human and female rat liver microsomes and expressed CYP3A4 and CYP3A5 were similar (0.39, 0.27, 0.28, 0.25, and 0.26 μM, respectively), while the Km values in male rat liver microsomes were 1.5 μM, indicating that AG-045572 is metabolized by different CYP3A isoenzymes in male and female rats.[1]

AG 045572 (10 mg/kg (i.v.) or 20 mg/kg (p.o.), one time) in intact male rats showed moderate T1/2, CL and Vss but low oral bioavailability, with The bioavailability is higher in female rats (24%), and the pharmacokinetics in castrated male rats are similar to those in female rats.[1]
The pharmacokinetics of AG 045572 (40 mg/kg; i.m.; twice a day for 3 days) in intact male rats changed, and the parameters were similar to those in female and castrated male rats.[1]