SKI2496 is an orally active GnRH receptor antagonist ( IC 50 : 0.25 nM for hGnRHR, 13.2 nM for monkey GnRHR, 279.2 nM for rat GnRHR). SKI2496 blocks Ca 2+ flux with an IC 50 value of 0.76 nM. SKI2496 inhibits ERK1/2 phosphorylation with an IC 50 value of 2.6 nM. SKI2496 inhbits serum LH concentrations, and can be used for research of sex hormone-dependent disorders.