title: Gonadal hormones masculinize and defeminize reproductive behaviors during puberty in the male Syrian hamster.
abstract: Three experiments were conducted to test whether testicular hormones secreted during puberty masculinize and defeminize the expression of adult reproductive behavior. Experiment 1 tested the hypothesis that gonadal hormones during puberty masculinize behavioral responses to testosterone (T) in adulthood. Male hamsters were castrated either before puberty (noTduringP) or after puberty (TduringP). All males were implanted with a 2.5-mg T pellet 6 weeks following castration and tested once for masculine reproductive behavior 7 days after the onset of T replacement. TduringP males displayed significantly more mounts, intromissions, and ejaculations than noTduringP males. Experiment 2 tested the hypothesis that gonadal hormones during puberty defeminize behavioral responses to estrogen (EB) and progesterone (P). Eight weeks following castration, noTduringP and TduringP males were primed with EB and P and tested for lordosis behavior with a stud male. Behavioral responses of males were compared to that of ovariectomized (OVX) and hormone primed females. NoTduringP males and OVX females displayed significantly shorter lordosis latencies than TduringP males. Experiment 3 investigated whether prolonged T treatment or sexual experience could reverse the deficits in masculine behavior caused by the absence of T during puberty. Extending the T treatment from 7 to 17 days did not ameliorate the deficits in masculine behavior caused by absence of T during puberty. Similarly, when the level of sexual experience was increased from one to three tests, the deficits in masculine behavior persisted. These studies demonstrate that gonadal hormones during puberty further masculinize and defeminize neural circuits and behavioral responsiveness to steroid hormones in adulthood.
authors.affiliation: Department of Psychology and Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Kalynn M
authors.initials: KM
authors.lastname: Schulz
authors.forename: Heather N
authors.initials: HN
authors.lastname: Richardson
authors.forename: Julia L
authors.initials: JL
authors.lastname: Zehr
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Osetek
authors.forename: Tami A
authors.initials: TA
authors.lastname: Menard
authors.forename: Cheryl L
authors.initials: CL
authors.lastname: Sisk
mesh_terms: D000818:Animals; D002369:Castration; D006224:Cricetinae; D004958:Estradiol / Q000502:physiology; D005260:Female; D012739:Gonadal Steroid Hormones / Q000502:physiology*; D008297:Male; D008647:Mesocricetus; D011374:Progesterone / Q000502:physiology; D012098:Reproduction / Q000502:physiology; D012727:Sex Characteristics; D012733:Sex Differentiation / Q000502:physiology; D012726:Sexual Behavior, Animal / Q000502:physiology*; D012741:Sexual Maturation / Q000502:physiology*; D013737:Testis / Q000502:physiology*; D013739:Testosterone / Q000502:physiology
chemical_list: D012739:Gonadal Steroid Hormones; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol