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。 家羊，季节性的 饲养员，将被用作动物模型，研究内部和外部 排卵开始的决定因素。 工作假设是 测试了光周期和生长相关的线索，通过撞击系统， 即控制第一次排卵时LH的脉冲式分泌。 实验将 进行，以确定是否褪黑激素是松果体产品， 在羔羊中传递光周期信息; 褪黑激素的便携式泵将进行成熟的女性， 松果体失去了神经支配 这项技术，加上人工 光处理，将被用来确定每个组成部分的作用， 启动青春期的新的三分光周期序列。 这 光周期序列，以及已开发的光周期， 延迟青春期，将被用作非侵入性探针， LH脉冲频率激素依赖性和激素非依赖性控制。 生长速度对首次排卵光周期要求的影响 将在体重受以下因素调节的条件下进行评估 营养水平。 将监测循环褪黑激素的模式， 确定当生长停止时， 营养有限。 发育迟缓模型，青春期延迟， 将用于研究有限营养对控制 激素依赖性和非激素依赖性LH脉冲分泌 机制等 在青春期的追赶生长阶段， 确定是否可以使用营养水平来设定频率 LH脉冲 LH的紧张性分泌水平与妊娠结局的关系 对雌二醇的正反馈作用作出反应的能力将是 在接受脉冲式输注的生长受限羔羊中检查 促性腺激素释放激素 将监测生长相关激素的模式和水平 在正常的性发育和青春期延迟诱导 不适当的光周期或生长不足。 这项研究将填补 我们对青春期的时间的认识存在着重大的空白 受外界环境的影响，在一个季节性繁殖的物种。 的 搏动性心脏病的营养和体重调节的研究结果 LH分泌将广泛应用于理解正常和 儿童青春期延迟。

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.