A method of inhibiting effects of growth hormone comprising administering to a human in need thereof an effective amount of a compound having formula (I), wherein R?1 and R3¿ are independently hydrogen, -CH¿3?, (a), or (b), wherein Ar is optionally substituted phenyl; R?2¿ is selected from the group consisting of pyrrolidine, hexamethyleneimino, and piperidino; or a pharmaceutically acceptable salt of solvate thereof.