Differential sensitivity of mounting and lordosis control systems to early androgen treatment in male and female hamsters.

The effects of early testosterone propionate (TP) treatment on the adult sexual behavior of hamsters were investigafed in two experiments. In Expt. I, mJe and female pup3 were injected with oil vehicle or 1, 5, 10, 50, 100, or 250 gg of TP 24 hr after birth. In EXPC. II, males and females received ejther oil or 10 pg of TP on the day of birth (Day l), Day 3, Day 5, Day 7, or Day 9. At 70 days of age all animals were gonadectomired and 10 days later tested for lord&s behavior aftw estrogen and progesterone priming. One week after the test for female behavior all females began receiving 500 fig of TP each day and were tested for mounting and intromission behavior three times at 10 day intervals. Lordosis behavior was inhibited by as little as 5 pg of TP given 24 hr after birth. In males this dose prodoced the maximal effect, but in females increasing dosages resulted in a proporlional decrease in lord&s duration. One pg of TP monatally facilitated later mounting and intromission behavior in females and 250 fig of TP was no more effective rhan 1 pg. Lordosis duration was inhibited in females by 1Org of TP on either Day 1 or 3, however, mounts and intromissions were facilitated by TP treatment on Day 1, 3, 5 or ‘7. These experiments demonstrate that the mechanisms mediating masculine behavior are mare sensitive to neonatal TP treatment than arc the mechanisms mediating Iordoris behavior.