PHYSIOLOGICAL IMPORTANCE OF GROWTH HORMONE PULSATILITY

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 在生长激素(GH)缺乏的成年人中，GH替代疗法正越来越多地被使用。GH通常作为每日皮下注射给患者使用。这会导致高生长激素水平，并在几个小时内缓慢下降。然而，在正常人中，生长激素是以脉冲形式分泌的，生长激素水平在一天中波动。在这项研究中，我们将解决生长激素水平模式是否对生长激素作用重要的问题。我们将研究30名患有生长激素缺乏症的成年人。这一诊断将通过胰岛素低血糖试验来确认。在这项测试中，静脉注射一定剂量的胰岛素，以降低血糖水平并引起低血糖症状。然后测量生长激素的响应。受试者将被允许进入GCRC，为期8天，共三次。他们将在生理盐水输注期间和生长激素注射期间进行研究，在一次入院期间作为连续静脉输注，在另一次入院期间作为每天6次不同的静脉剂量。肝脏的反应将通过做红霉素呼气测试和测量血脂水平来测试。骨骼的反应将通过几项血液和尿液测试来评估，肌肉的反应将通过对大腿肌肉进行针刺活检来评估。不同类型的生长激素对血糖和胰岛素水平的影响将通过静脉葡萄糖耐量试验来研究。这项研究的结果将对设计更好的生长激素释放方法具有重要意义。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In adults with growth hormone (GH) deficiency, GH replacement therapy is being increasingly utilized. GH is usually administered to patients as a daily subcutaneous injection. This leads to high GH levels that slowly decrease over several hours. However, in normal individuals GH is secreted in pulses and the GH levels fluctuate throughout the day. In this study we will address the question of whether the pattern of GH levels is important for GH action. We will study thirty adults with GH deficiency. The diagnosis will be confirmed by insulin hypoglycemia test. During this test a dose of insulin is given intravenously to decrease the blood glucose levels and cause symptoms of hypoglycemia. The GH response is then measured. The subjects will be admitted to the GCRC for 8 days three times. They will be studied during normal saline infusion, and during GH administration as a continuous intravenous infusion during one admission and as 6 separate intravenous doses per day during the other admission. The response of the liver will be tested by doing an erythromycin breath test, and measuring plasma lipid levels. The response of the bones will be assessed by several blood and urine tests, and the response of the muscles will be assessed by doing a needle biopsy of a thigh muscle. The effects of the different patterns of GH on glucose and insulin levels will be studied by intravenous glucose tolerance test. The results of this study will be important in the design of better GH delivery methods.'