IMPACT OF REDUCED GLUCOSE INFUSION RATE AND INSULIN INFUSION, RESPECTIVELY, O

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。 摘要 极低出生体重(ELBW)新生儿(出生体重1000克)，通常在他们的病程中需要完全肠外营养(TPN)，直到他们对肠道喂养的耐受性良好为止。这些婴儿面临葡萄糖代谢紊乱和能量补充不足的风险。他们有很高的高血糖发生率(50-80%)。通常，根据高血糖的严重程度和患者的临床表现，可以通过降低葡萄糖输注速率和/或静脉注射胰岛素来治疗这些高血糖。我们不知道葡萄糖异生是受到葡萄糖输注速率降低引起的葡萄糖和胰岛素浓度变化的影响，还是受到固定的胰岛素输注的影响。本研究的目的是确定将葡萄糖输注速率降低到相当于正常葡萄糖转换率的一半和固定胰岛素输注对低出生体重儿葡萄糖和蛋白质代谢的影响。对我们来说，了解这些非常小的婴儿的葡萄糖代谢生理学是很重要的，因为这将使我们能够设计出足够的肠外营养，使这些婴儿在提供足够能量摄入的同时保持正常的血糖。 假设 1.由于葡萄糖输注速率降低到3 mg/kg/min，血糖和胰岛素水平下降，糖异生速率不会改变。 2.固定输注足以使血浆胰岛素浓度达到高生理范围(-80-100uU/ml)的胰岛素将： A.没有明显抑制糖异生的速度 提高葡萄糖利用率，无论体重、胎龄和临床状态如何，但增加葡萄糖利用率将与体重成正比 C.增加蛋白质合成 具体目标 本研究的目的是确定将葡萄糖输注速度降低到相当于正常葡萄糖周转率的一半(同时保持肠外脂肪和氨基酸的输注速度不变)和固定胰岛素输注对极低出生体重儿葡萄糖利用率和产生率的代谢影响。这将使用稳定的同位素-GCMS技术进行。这将使我们能够确定不同的葡萄糖输注速度和血浆胰岛素水平对患病新生儿的代谢影响。

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. ABSTRACT Extremely low birth weight (ELBW) newborns (birth weight <1000g), usually require Total Parenteral Nutrition (TPN) during the course of their illness and until their ability to tolerate enteral feeds is well established. These infants are at risk of disturbed glucose metabolism and inadequate energy supplementation. They have a very high incidence of hyperglycemia (50-80%). Usually, these high blood glucose values are being treated with reduction of the glucose infusion rate and/or with intravenous insulin, depending on the severity of the hyperglycemia and the patient's clinical picture. We do not know whether gluconeogenesis is affected by the changes in glucose and insulin concentrations resulting from reduced glucose infusion rates or by a fixed insulin infusion. the purpose of this study is to determine the effect of reducing the glucose infusion rate to correspond to half the normal glucose turn over rate and of a fixed insulin infusion, on glucose and protein metabolism in ELBW infnats. It is important for us to learn about the physiology of glucose metabolism in these very small infants for it will enable us to design an adequate parenteral nutrition that renders these infants normoglycemic while providing a sufficient energy intake. HYPOTHESIS 1. Rates of gluconeogenesis do not change in response to a decrease in blood levels of glucose and insulin, resulting from a decrease in the glucose infusion rate to 3mg/kg/min. 2. A fixed infusion of insulin sufficient to achieve a plasma insulin concentration in the high physiologic range (-80-100uU/ml) will: a. Not acutely suppress rates of gluconeogenesis b. Increase glucose utilization regardless of body weight, gestational age and clinical status, but increasing the glucose utilization will be proportional to body weight c. Increase protein synthesis SPECIFIC AIMS The purpose of this study is to determine the metabolic effects of changes in glucose and insulin concentration resulting from reducing the infusion rate of glucose to correspond to half normal glucose turnover (while maintaining the infusion rates of parenteral lipids and amino acids unchanged) and from a fixed insulin infusion on rates of glucose utilization and production in extremely low birth weight infants. This will be performed using Stable Isotope-GCMS techniques. This will allow us to determine the metabolic effects of different glucose infusion rates and plasma insulin levels in sick newborn infants.