Yahr P, Stephens D R
Department of Psychobiology, University of California, Irvine 92717.
Horm Behav. 1987 Sep;21(3):331-46. doi: 10.1016/0018-506x(87)90018-3.
The sexual and scent marking behaviors of male gerbils are stimulated by testosterone (T) action in the preoptic area (POA) of the hypothalamus. The sexually dimorphic area (SDA) in the posterior POA, which also responds to T, is implicated in this process. This research studied the sensitivities of mating, marking, and the SDA to T metabolites and other steroids. Experiment 1 focused on mating. Male gerbils were implanted at castration with 2-mm Silastic capsules containing T, dihydrotestosterone (DHT), 19-nortestosterone (19-nor T), estradiol (E), or no hormone and were tested 3-7 weeks later. T, E, and 19-nor T maintained intromissions, but E-treated males rarely ejaculated. Controls and DHT-treated males stopped mounting. Experiment 2 compared the ability of these steroids to reinstate marking and mating using the same dose and a larger one (5 mm). Androstenedione, 19-hydroxytestosterone (19-OHT), and E plus DHT were studied as well. Volumes of the SDA and SDA pars compacta (SDApc) were also measured. Only T, 19-nor T, E, and E + DHT reinstated sexual behavior, but all steroids except 19-OHT stimulated marking. E and DHT synergized to elicit mating. For marking, they were no more effective together than alone. Steroid-treated males had larger SDAs than controls. Moreover, steroids that stimulated sexual activity produced larger SDAs than steroids that did not. SDA size correlated with copulatory rate, but not with copulatory efficiency. SDApc size correlated with copulatory efficiency, but not with copulatory rate. Like copulatory rate and efficiency, sizes of the SDA and SDApc did not correlate with each other.
雄性沙鼠的性行为和气味标记行为是由下丘脑视前区（POA）中的睾酮（T）作用所刺激的。POA后部的性二态区（SDA）也对T有反应，该区域参与了这一过程。本研究考察了交配、标记行为以及SDA对T代谢产物和其他类固醇的敏感性。实验1聚焦于交配行为。雄性沙鼠在阉割后被植入含有T、双氢睾酮（DHT）、19-去甲睾酮（19-去甲T）、雌二醇（E）或不含激素的2毫米硅橡胶胶囊，并在3至7周后进行测试。T、E和19-去甲T维持了插入行为，但接受E处理的雄性很少射精。对照组和接受DHT处理的雄性停止了爬跨行为。实验2使用相同剂量和更大剂量（5毫米）比较了这些类固醇恢复标记行为和交配行为的能力。还研究了雄烯二酮、19-羟基睾酮（19-OHT）以及E加DHT。同时测量了SDA和SDA致密部（SDApc）的体积。只有T、19-去甲T、E以及E + DHT恢复了性行为，但除19-OHT外的所有类固醇都刺激了标记行为。E和DHT协同引发交配行为。对于标记行为，它们共同作用时并不比单独作用时更有效。接受类固醇处理的雄性沙鼠的SDA比对照组更大。此外，刺激性活动的类固醇所产生的SDA比未刺激的类固醇更大。SDA大小与交配频率相关，但与交配效率无关。SDApc大小与交配效率相关，但与交配频率无关。与交配频率和效率一样，SDA和SDApc的大小彼此不相关。
