Ri. Wood, ESTRADIOL, BUT NOT DIHYDROTESTOSTERONE, IN THE MEDIAL AMYGDALA FACILITATES MALE HAMSTER SEX BEHAVIOR, Physiology & behavior, 59(4-5), 1996, pp. 833-841
In the male Syrian hamster, the medial amygdaloid nucleus (Me) and med
ial preoptic area (MPOA) are critical for expression of male mating be
havior. These regions contain steroid receptor-containing neurons that
transduce hormonal signals essential for copulation. In castrated mal
es bearing an intracerebral steroid implant in the MPOA, testosterone
or estradiol can facilitate sexual activity. However, DHT is without e
ffect. Testosterone can also stimulate mating when implanted in the Me
. The present study determined if estradiol or DHT had behavioral acti
vity in the Me. Twenty adult male hamsters were selected for vigorous
sexual behavior. Twelve weeks after castration, sexual behavior was as
sessed and each male received a single intracranial implant (23-gauge
tubing packed with crystalline estradiol or DHT, n = 10 each) placed s
tereotaxically into posterior Me (MeP). Behavior was examined after su
rgery to determine if androgens or estrogens in MeP could stimulate se
xual behavior above that observed after castration. Mating behavior in
DHT-implanted males was not significantly different from castrates. H
owever, males with estradiol implants displayed significantly more cop
ulatory and noncopulatory sexual activity after surgery compared to ma
les with DHT implants. These results suggest that testosterone facilit
ation of mating behavior in MeP is mediated by aromatization to estrad
iol, and that DHT is not behaviorally active in this nucleus.