Effect of a Single Prepubertal Injection of Testosterone Propionate on Adult Bisexual Behavior of Male Hamsters Castrated at Birth1

Twenty-nine male hamsters were castrated at birth (Day 1). Two groups were treated with oil or 500 µg of testosterone propionate (TP) on Day 1 and a third group was treated with 500 µg of TP on Day 15. Nine males and 9 females were gonadectomized in adulthood to serve as controls. All neonatal castrates were tested as adults for masculine mating behavior with receptive females and for feminine mating behavior with stimulus males. Tests were conducted over a 2-month period under 4 sequential conditions in which the neonatal castrates received: 1) no exogenous steroids, 2) 10 µg of estradiol benzoate (EB) and .4 mg of progesterone (P), 36 and 6 hr, respectively, before testing, 3) no exogenous steroids, and 4) 200 µg of TP a day for 29 days prior to testing. When treated with EB and P the neonatal castrates which received oil on Day 1 or TP on Day 15 showed feminine behavior (lordosis) equal in most respects to that of control females. After the TP treatment in the fourth condition the same groups mounted estrous females but never achieved intromission. Unlike males castrated in adulthood, the neonatal castrates which received TP on Day 1 did not display lordosis when treated with EB and P. When treated with TP in adulthood and tested with receptive females they achieved intromission and ejaculated, but with lower frequency than males castrated in adulthood. (Endocrinology87: 934, 1970)