Department of Psychology, Michigan State University, East Lansing, MI 48824, USA.
Horm Behav. 2012 Jul;62(2):180-5. doi: 10.1016/j.yhbeh.2012.07.002. Epub 2012 Jul 13.
The rewarding value of female sexual stimuli develops across puberty, as sexually-naïve adult, but not prepubertal, male hamsters show a conditioned place preference (CPP) for both vaginal secretions and a receptive female. Similarly, only adults show an endogenous testosterone surge when they encounter vaginal secretions. Testosterone by itself can condition a place preference in male rodents. Therefore, Experiment 1 assessed whether the endogenous testosterone surge elicited by vaginal secretions is necessary to show a CPP. Both gonad-intact and gonadectomized, testosterone-treated adult males showed a CPP for vaginal secretions, indicating that the rewarding value of this social cue is independent of an endogenous testosterone surge. However, organizational effects of pubertal testosterone could be necessary for adolescent development of social reward, as pubertal testosterone organizes adult-typical expression of sexual behavior. To investigate this possibility, in Experiment 2, sexually-naïve prepubertal and adult male hamsters were gonadectomized and received testosterone-filled capsules four weeks later. Testing began after two weeks of testosterone replacement. Adult males showed a CPP for both vaginal secretions and a receptive female, whether or not they experienced pubertal testosterone. Thus, the acquisition of positive valence of sexual stimuli is not organized by pubertal testosterone. Taken together, the ability of female sexual stimuli to serve as an unconditioned reward to adult male hamsters is independent of the chemosensory-induced endogenous testosterone surge and also organizational effects of pubertal testosterone. Instead, sexual reward may be dependent either on activational effects of testosterone or gonadal hormone-independent mechanisms.
女性性刺激的奖赏价值在青春期发展，因为性幼稚的成年但未成熟的雄性仓鼠对阴道分泌物和接受的雌性都表现出条件位置偏好 (CPP)。同样，只有成年雄性在遇到阴道分泌物时才会出现内源性睾酮激增。睾酮本身可以在雄性啮齿动物中调节位置偏好。因此，实验 1 评估了阴道分泌物引起的内源性睾酮激增是否对 CPP 是必要的。未去势和去势、睾酮处理的成年雄性都对阴道分泌物表现出 CPP，表明这种社交线索的奖赏价值独立于内源性睾酮激增。然而，青春期睾酮的组织效应可能是青春期社会奖励发展所必需的，因为青春期睾酮组织了成年典型的性行为表达。为了研究这种可能性，在实验 2 中，性幼稚的青春期前和成年雄性仓鼠被去势，并在四周后接受充满睾酮的胶囊。在接受两周的睾酮替代治疗后开始测试。成年雄性对阴道分泌物和接受的雌性都表现出 CPP，无论它们是否经历过青春期睾酮。因此，性刺激的正性效价的获得不受青春期睾酮的组织。总之，雌性性刺激作为成年雄性仓鼠的无条件奖励的能力独立于化学感觉诱导的内源性睾酮激增，也独立于青春期睾酮的组织效应。相反，性奖励可能依赖于睾酮的激活作用或与性腺激素无关的机制。
