Aromatase inhibition depresses ultrasound production and copulation in male hamsters.

Rates of ultrasound production and copulatory behavior were observed in castrated male hamsters maintained on 100 micrograms/day of injected testosterone propionate (TP). Groups matched on their initial levels of behavior received either continued treatment with TP alone, or TP together with 6 mg/day injections of the aromatase inhibitor 1,4,6-androstatriene-3,17-dione (ATD). Testing at 11-15 days after the start of these treatments revealed deficits in the sexual behaviors of the subjects in the latter group. Specifically, these males showed lower rates of ultrasound production and intromission during, as opposed to before, treatment with ATD. These results support previous work suggesting that aromatization plays significant roles in the mediation of androgenic effects on both the courtship and copulatory behaviors of male hamsters.