CONTROL OF GONADOTROPIN SECRETION DURING LACTATION

哺乳期哺乳的生殖状态，发生在所有哺乳动物中， 与生殖周期的抑制有关， 促性腺激素释放激素抑制排卵 （GnRH），下丘脑神经内分泌神经元调节 生殖 我们研究的重点是确定传入神经 哺乳期哺乳刺激激活的神经通路 负责抑制GnRH神经元功能。 在过去的一年里，我们做了以下观察：1）使用神经元 束跟踪技术和共聚焦显微镜，我们已经表明， 哺乳刺激激活的NPY神经元投射到 含有GnRH神经元并与GnRH神经元过程接触。 这些结果表明，哺乳可能是一种神经机制， 抑制GnRH神经元活性。 2)食物摄入量的大幅增加 在哺乳期最有可能发生的反应， 代谢活动的信号变化，如瘦素（a 饱腹感诱导物质）和刺豚鼠相关转录物（ART， 诱发肥胖症）。 在哺乳期，血液中的瘦素水平大大降低， 抑制，而ART表达在下丘脑中增加。 目前实验室的研究正在研究 瘦素和ART的变化与NPY神经元的增加之间 活动和食物摄入。 此外，我们正在探索可能的 摄食调节和促性腺激素调节之间的相互作用 在哺乳期间释放激素神经元活动。 公 许多不孕症的原因都与 能量稳态，如运动诱发的闭经， 神经性厌食症 了解这些机制， 哺乳刺激对GnRH神经元功能产生抑制作用 提供与灵长类动物（包括人类）相关的信息， 其中生殖神经内分泌轴调节卵巢 循环性也受到抑制。 这些研究与妇女的 生殖健康，因为它们将增加我们对 下丘脑原因不孕症，并提供新的方法， 避孕。

The reproductive state of lactation, which occurs in all mammals, is associated with an inhibition of reproductive cyclicity and ovulation due to a suppression of gonadotropin releasing hormone (GnRH), the hypothalamic neuroendocrine neurons regulating reproduction. The focus of our studies is to identify the afferent neuronal pathways activated during lactation by the suckling stimulus that are responsible for the suppression of GnRH neuronal function. This past year, we made the following observations 1) Using neuronal tract tracing techniques and confocal microscopy, we have shown that NPY neurons activated by the suckling stimulus project to areas containing GnRH neurons and make contact with GnRH neuronal processes. These results suggest a possible neuronal mechanism by which suckling inhibits GnRH neuronal activity. 2) The large increase in food intake during lactation most likely occurs in response to substances that signal changes in metabolic activity, such as leptin (a satiety-inducing substance) and agouti-related transcript (ART, induces obesity). During lactation, blood leptin levels are greatly suppressed, whereas ART expression is increased in the hypothalamus. Current studies in the laboratory are examining the relationship between the changes in leptin and ART and the increase in NPY neuronal activity and food intake. In addition, we are exploring possible interactions between the regulation of food intake and of gonadotropin releasing hormone neuronal activity during lactation. It is well established that many causes of infertility are related to changes in energy homeostatis, such as in exercised-induced amenorrhea and anorexia nervosa. An understanding of the mechanisms by which the suckling stimulus imposes an inhibition on GnRH neuronal function provides information that is relevant to primates (including humans), in which the reproductive neuroendocrine axis regulating ovarian cyclicity is also inhibited. These studies have relevance to women's reproductive health as they will increase our understanding of hypothalamic causes of infertility and provide new approaches for contraception.