Brodsky I G, Devlin J T
Metabolic Unit, University of Vermont, Burlington 05405, USA.
Am J Physiol. 1996 Jan;270(1 Pt 1):E148-57. doi: 10.1152/ajpendo.1996.270.1.E148.
We studied subjects with insulin-dependent diabetes mellitus (IDDM) and controls by administering primed continuous infusions of L-[1-13C,15N)]leucine and L-[2,3-13C2]alanine to measure whole body and forearm metabolism of these amino acids during ample protein intake and again after 4 wk of moderately restricted protein intake. Decreased rates of whole body protein degradation, leucine transamination, leucine oxidation, and increased forearm alanine release produced by dietary protein restriction occurred equivalently in IDDM subjects under short-term tightly managed glycemia and in controls. Dietary protein restriction did not affect whole body alanine appearance or forearm leucine appearance, disposal, or balance in IDDM subjects or controls. IDDM subjects differed from controls only in that normal forearm leucine balance was maintained at higher rates of leucine appearance and disposal. We conclude that IDDM subjects adapt normally to dietary protein restriction. Undernutrition during moderate protein deprivation in these patients likely occurs during episodes of poor glycemic control.
我们通过给予L-[1-¹³C,¹⁵N]亮氨酸和L-[2,3-¹³C₂]丙氨酸的预充连续输注，对胰岛素依赖型糖尿病（IDDM）患者和对照组进行了研究，以测量充足蛋白质摄入期间以及适度限制蛋白质摄入4周后这些氨基酸的全身和前臂代谢情况。在短期严格控制血糖的IDDM患者和对照组中，饮食蛋白质限制所导致的全身蛋白质降解率、亮氨酸转氨作用、亮氨酸氧化率降低以及前臂丙氨酸释放增加的情况是相同的。饮食蛋白质限制对IDDM患者或对照组的全身丙氨酸生成或前臂亮氨酸生成、处置或平衡没有影响。IDDM患者与对照组的不同之处仅在于，正常的前臂亮氨酸平衡是在更高的亮氨酸生成和处置率下维持的。我们得出结论，IDDM患者能正常适应饮食蛋白质限制。这些患者在适度蛋白质缺乏期间的营养不良可能发生在血糖控制不佳的时期。
