REGULATION OF PROTEOLYSIS IN PREMATURE NEONATES

这项建议的总体目标是进一步界定该条例， 蛋白质水解的影响。因为蛋白质水解 蛋白质合成最终决定了蛋白质的增长和 生长将发生，确定潜在的调节蛋白水解， 作为一种手段，以最大限度地增加蛋白质的营养， 弱势群体。外源性胰岛素目前用于 极早产儿，以促进生长，虽然效果 胰岛素对蛋白质代谢的影响尚不清楚。此外，胃肠外 营养液经常用于患病和早产新生儿， 无法耐受肠道喂养。氨基酸的数量和质量 提供给这些新生儿的酸可能是一个关键因素， 最大化蛋白质积累。这项建议的具体目标是： 1)确定连续胰岛素输注如何影响 极早产儿2）评估分级氨基的程度 酸抑制早产儿的蛋白水解，3）确定是否 加入酪氨酸和半胱氨酸（被认为是必需氨基酸， 早产儿）与目前可用的氨基酸溶液相比， 进一步提高蛋白质增长率。每一个具体目标 将使用必需氨基酸的稳定同位素示踪剂进行研究， 酸亮氨酸和苯丙氨酸，其内源性的出现率是 反映了全身蛋白质的分解进行这些研究将 提供了深入了解蛋白质增长的生理学，因此， 成长过程最终，这些信息可以作为基础， 改善早产儿的营养管理。

The overall objective of this proposal is to further define the regulation of proteolysis in premature neonates. As the balance between proteolysis and protein synthesis ultimately determines whether protein accretion and growth will occur, identifying potential regulators of proteolysis may serve as a means to maximize protein accretion in this nutritionally vulnerable population. Exogenous insulin is currently being used in extremely premature neonates to promote growth, although the effect of insulin on protein metabolism is unknown. In addition, parenteral nutrition solutions are frequently used in sick and premature neonates who are unable to tolerate enteral feeding. The quantity and quality of amino acids provided to these neonates is likely to be a critical factor in maximizing protein accretion. The specific aims of this proposal are to: 1)determine how a continuous insulin infusion affects proteolysis in the extremely premature neonate 2)evaluate the extent to which graded amino acids suppress proteolysis in premature infants and 3)determine whether adding tyrosine and cysteine (thought to be essential amino acids in premature infants) to currently available amino acid solutions will further improve rates of protein accretion. Each of these specific aims will be pursued using the stable isotope tracers of the essential amino acids leucine and phenylalanine, whose endogenous rate of appearance is reflective of whole body proteolysis. Performing these studies will provide insight into the physiology of protein accretion, and thus the growth process. Ultimately, this information may serve as the basis for improved nutritional management of premature infants.