Effects of metyrapone, mifepristone, and spironolactone on pro-social and amphetamine-stimulated calling. Escalating doses of metyrapone (50 or 100 mg/kg, i.p., once a week) almost completely suppressed the number of 50-kHz ultrasonic vocalizations (USVs) emitted by rats that were housed in pairs during recording, compared with vehicle administration (A). Conversely, escalating doses of mifepristone (40 or 100 mg/kg, s.c., once a week) or spironolactone (50 or 75 mg/kg, s.c., once a week) did not affect pro-social calling (B–C). In rats that were individually housed during recordings, co-administration of metyrapone (100 mg/kg, i.p.) almost completely suppressed the number of 50-kHz USVs recorded after the administration of amphetamine (1 mg/kg, i.p.), compared with vehicle co-administration (D). Conversely, co-administration of mifepristone (40 or 100 mg/kg, s.c.) or spironolactone (50 or 75 mg/kg, s.c.) had no influence on amphetamine-stimulated calling (E–F). AMPH, amphetamine; METY, metyrapone; MIFE, mifepristone; SPIRO, spironolactone; VEH, vehicle. *P<.05 vs VEH; #P<.05 vs VEH + AMPH. n=10.