Mutations remote from the human gonadotropin-releasing hormone (GnRH) receptor-binding sites specifically increase binding affinity for GnRH II but not GnRH I: evidence for ligand-selective, receptor-active conformations - Lu,Z.L.; Gallagher,R.; Sellar,R.; Coetsee,M.; Millar,R.P. (J Biol Chem, 2005)