NEUROENDOCRINOLOGY OF PUBERTY

这项研究的总体目标是确定神经内分泌 控制青春期开始的机制。家养绵羊，季节性的 饲养员，将作为动物模型来研究内外 排卵启动的决定因素。工作假设将是 通过影响系统来测试光周期和与生长相关的线索 即控制搏动性黄体生成素分泌时间的首次排卵。实验将会 以确定褪黑素是否是松果体产品 在羔羊体内传递光周期信息；长时间输注 便携式泵的褪黑素将在成熟的女性身上进行 已经失去松果体的神经。这种技术，再加上人工的 光处理，将被用来确定每个成分的作用 启动青春期的新的三部光周期序列。这 光周期序列，以及已经发展到 延缓青春期，将被用作无创探头来检查 黄体生成素脉冲频率的类固醇依赖和非类固醇非依赖性控制。 生长速度对第一次排卵光周期需要的影响 将在以下条件下进行评估：体重受 营养水平。循环中的褪黑素模式将被监测以 确定当生长停止时是否感知到光周期信号 有限的营养。生长迟缓模型中，青春期被推迟， 将被用来研究有限营养对控制肺炎的影响 激素依赖和非激素非依赖性促黄体生成素的搏动性分泌 机械装置。在青春期开始的追赶生长阶段，它会 确定是否可以使用营养水平来设置频率 黄体生成素的脉搏。强直性促黄体生成素分泌水平与血清黄体生成素水平的关系 对雌二醇的正反馈作用作出反应的能力将是 对生长受限的羔羊进行了检查，这些羔羊接受了脉冲输注 GnRH。将监测与生长相关的激素的模式和水平 在性发育正常期和青春期延迟期 不适当的光周期或生长不充分。这项研究将填补 在我们对青春期的时间如何的了解上存在着重要的差距 受外界环境影响的季节性繁殖物种。这个 脉搏草营养与体重调节的研究结果 促黄体生成素的分泌将对理解正常和 儿童的青春期延迟。

The overall objective of the research is to determine neuroendocrine mechanisms governing onset of puberty. The domestic sheep, a seasonal breeder, will be used as the animal model to study internal and external determinants for initiation of ovulation. The working hypothesis will be tested that photoperiod and growth-associated cues, by impinging on systems that control pulsatile LH secretion time first ovulation. Experiments will be conducted to determine if melatonin is the pineal product that transduces photoperiodic information in the lamb; prolonged infusions of melatonin by portable pumps will be carried out in maturing females that have denervated pineal glands. This technique, coupled with artificial light treatments, will be used to determine the role of each component of the novel tripartite photoperiod sequence that initiates puberty. This photoperiod sequence, as well as photoperiods that have been developed to delay puberty, will be used as noninvasive probes to examine steroid-dependent and steroid-independent control of LH pulse frequency. The effect of growth rate on photoperiodic requirements for first ovulation will be evaluated under conditions in which body weight is regulated by level of nutrition. Patterns of circulating melatonin will be monitored to determine if photoperiod cues are perceived when growth ceases under limited nutrition. The growth-retarded model, in which puberty is delayed, will be used to study the effects of limited nutrition on control of pulsatile LH secretion by steroid-dependent and steroid-independent mechanisms. During the catch-up growth phase when puberty occurs, it will be determined whether level of nutrition can be used to set the frequency of LH pulses. The relationship between level of tonic LH secretion and the ability to respond to the positive feedback action of estradiol will be examined in growth-restricted lambs treated with a pulsatile infusion of GnRH. Patterns and levels of growth-associated hormones will be monitored during normal sexual development and in delayed puberty induced by inappropriate photoperiod or by inadequate growth. The research will fill and important gap in our knowledge of how the timing of puberty is influenced by external environment in a seasonally breeding species. The results of investigations of nutrition and weight regulation of pulsatile LH secretion will have broad application to the understanding of normal and delayed puberty in children.