Richardson Heather N, Nelson Aaron L A, Ahmed Eman I, Parfitt David B, Romeo Russell D, Sisk Cheryl L
Departments of Psychology and Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA.
Gen Comp Endocrinol. 2004 Sep 15;138(3):211-7. doi: 10.1016/j.ygcen.2004.06.008.
In many species chemosensory stimuli function as important signals that influence reproductive status. Neurons synthesizing the peptide gonadotropin-releasing hormone (GnRH) are critical mediators of reproductive function via their regulation of the hypothalamic-pituitary-gonadal (HPG) axis, and they are thought to be responsive to chemosensory information. In the present study, we sought to elucidate the effects of female chemosensory stimuli on the HPG axis in sexually naive adult male Syrian hamsters. In Experiment 1, serial blood samples were collected from catheterized male hamsters following exposure to female pheromones in order to characterize the luteinizing hormone (LH) response to this chemosensory stimulus. In Experiment 2, brains and terminal blood samples were collected from animals 0, 60, and 120 min following pheromone exposure. GnRH mRNA was measured in brain tissue sections using in situ hybridization, and plasma concentrations of LH and testosterone were measured using radioimmunoassay. Data from Experiment 1 indicated that female pheromones elicited a rapid rise in plasma LH that peaked at 15 min and returned to baseline 45 min after exposure. In Experiment 2, testosterone was elevated in terminal blood samples obtained 60 min, but not 120 min, after exposure to pheromones. LH levels were unaffected at both of these time points. The chemosensory-induced increases in LH and testosterone release were not accompanied by subsequent changes in GnRH mRNA over the time course studied. These data suggest that while activation of the male HPG axis by female pheromones involves release of GnRH, it does not involve increases in GnRH mRNA 1-2 h after pheromonal stimulation as a mechanism for replenishment of released peptide.
在许多物种中，化学感应刺激作为影响生殖状态的重要信号发挥作用。合成肽促性腺激素释放激素（GnRH）的神经元通过调节下丘脑 - 垂体 - 性腺（HPG）轴，是生殖功能的关键调节因子，并且它们被认为对化学感应信息有反应。在本研究中，我们试图阐明雌性化学感应刺激对性成熟前成年雄性叙利亚仓鼠HPG轴的影响。在实验1中，在将雄性仓鼠暴露于雌性信息素后，从插管的雄性仓鼠收集系列血样，以表征促黄体生成素（LH）对这种化学感应刺激的反应。在实验2中，在信息素暴露后0、60和120分钟从动物收集大脑和末梢血样。使用原位杂交在脑组织切片中测量GnRH mRNA，并使用放射免疫测定法测量LH和睾酮的血浆浓度。实验1的数据表明，雌性信息素引起血浆LH的快速升高，在15分钟达到峰值，并在暴露后45分钟恢复到基线水平。在实验2中，在暴露于信息素后60分钟而非120分钟获得的末梢血样中睾酮升高。在这两个时间点LH水平均未受影响。在所研究的时间过程中，化学感应诱导的LH和睾酮释放增加并未伴随GnRH mRNA的后续变化。这些数据表明，虽然雌性信息素对雄性HPG轴的激活涉及GnRH的释放，但在信息素刺激后1 - 2小时内，它并不涉及GnRH mRNA的增加作为补充释放肽的机制。
