Bottjer S W, Schoonmaker J N, Arnold A P
J Neurobiol. 1986 Nov;17(6):605-12. doi: 10.1002/neu.480170605.
Gonadal hormones can produce striking behavioral and neural plasticity in adult organisms. For example, systemic administration of testosterone to adult female canaries induces the development of male-typical song behavior and results in a striking increase in the size of brain nuclei that are known to be involved with song control. The mechanism whereby androgens produce such neural plasticity is not known, although it has seemed likely that growth-promoting effects of androgens are due to a direct induction of protein synthesis in cells containing hormone receptors (following activation of specific genes by the hormone-receptor complex). In this experiment we have examined the trophic effect of testosterone in the song-control nucleus HVc (caudal nucleus of the ventral hyperstriatum), which has been shown to contain androgen-concentrating cells as well as neurons that are especially responsive to conspecific song. We report here that testosterone administration increases the volume of HVc in hearing adult female canaries only; testosterone-induced growth of HVc is greatly attenuated in birds that are deprived of auditory stimulation via deafening. Thus, testosterone treatment alone is not a sufficient stimulus for neural growth in HVc. This result suggests that testosterone does not stimulate growth solely via a direct action on hormone receptors in HVc, but rather that testosterone and sensory stimulation can act synergistically to produce structural plasticity in the adult brain.
性腺激素能够在成年生物体中产生显著的行为和神经可塑性。例如，对成年雌性金丝雀全身注射睾酮会诱导雄性典型鸣叫行为的发展，并导致已知参与鸣叫控制的脑核体积显著增加。尽管雄激素产生这种神经可塑性的机制尚不清楚，但雄激素的促生长作用似乎是由于在含有激素受体的细胞中直接诱导蛋白质合成（在激素 - 受体复合物激活特定基因之后）。在本实验中，我们研究了睾酮在鸣叫控制核团HVC（腹侧纹状体尾核）中的营养作用，该核团已被证明含有雄激素浓缩细胞以及对同种鸣叫特别敏感的神经元。我们在此报告，仅对成年有听力的雌性金丝雀注射睾酮会增加HVC的体积；在通过致聋剥夺听觉刺激的鸟类中，睾酮诱导的HVC生长会大大减弱。因此，单独的睾酮治疗并不是HVC神经生长的充分刺激因素。这一结果表明，睾酮并非仅通过直接作用于HVC中的激素受体来刺激生长，而是睾酮和感觉刺激可以协同作用，在成体大脑中产生结构可塑性。
