An LHR antagonist (IC50s 185 and 46 nM for the human and rat receptors respectively) selective for LHR over TSH and FSH receptors (IC50s 24 and >16 UM respectively for the human receptors) and a panel of 25 GPCRs at 10 UM reduces serum levels of estradiol in female rats at 12.5 mg/kg per day