Gutniak M, Blomqvist G, Widén L, Stone-Elander S, Hamberger B, Grill V
Department of Endocrinology, Karolinska Hospital and Institute, Stockholm, Sweden.
Am J Physiol. 1990 May;258(5 Pt 1):E805-12. doi: 10.1152/ajpendo.1990.258.5.E805.
We used D-[U-11C]glucose to evaluate transport and metabolism of glucose in the brain in eight nondiabetic and six insulin-dependent diabetes mellitus (IDDM) subjects. IDDM subjects were treated by continuous subcutaneous insulin infusion. Blood glucose was regulated by a Biostator-controlled glucose infusion during a constant insulin infusion. D-[U-11C]-glucose was injected for positron emission tomography studies during normoglycemia as well as during moderate hypoglycemia [arterial plasma glucose 2.74 +/- 0.14 in nondiabetic and 2.80 +/- 0.26 mmol/l (means +/- SE) in IDDM subjects]. Levels of free insulin were constant and similar in both groups. The tracer data were analyzed using a three-compartment model with a fixed correction for 11CO2 egression. During normoglycemia the influx rate constant (k1) and blood-brain glucose flux did not differ between the two groups. During hypoglycemia k1 increased significantly and similarly in both groups (from 0.061 +/- 0.007 to 0.090 +/- 0.006 in nondiabetic and from 0.061 +/- 0.006 to 0.093 +/- 0.013 ml.g-1.min-1 in IDDM subjects). During normoglycemia the tracer-calculated metabolism of glucose was higher in the whole brain in the nondiabetic than in the diabetic subjects (22.0 +/- 1.9 vs. 15.6 +/- 1.1 mumol.100 g-1.min-1, P less than 0.01). During hypoglycemia tracer-calculated metabolism was decreased by 40% in nondiabetic subjects and by 28% in diabetic subjects. The results indicate that uptake of glucose is normal, but some aspect of glucose metabolism is abnormal in a group of well-controlled IDDM subjects.
我们使用D-[U-11C]葡萄糖来评估8名非糖尿病受试者和6名胰岛素依赖型糖尿病（IDDM）受试者大脑中葡萄糖的转运和代谢情况。IDDM受试者通过持续皮下胰岛素输注进行治疗。在持续输注胰岛素期间，通过生物人工肝控制的葡萄糖输注来调节血糖。在血糖正常以及中度低血糖期间（非糖尿病受试者动脉血浆葡萄糖为2.74±0.14，IDDM受试者为2.80±0.26 mmol/l[均值±标准误]）注射D-[U-11C]葡萄糖以进行正电子发射断层扫描研究。两组的游离胰岛素水平恒定且相似。使用三室模型对示踪剂数据进行分析，并对11CO2逸出进行固定校正。在血糖正常期间，两组之间的流入速率常数（k1）和血脑葡萄糖通量没有差异。在低血糖期间，两组的k1均显著增加且相似（非糖尿病受试者从0.061±0.007增加到0.090±0.006，IDDM受试者从0.061±0.006增加到0.093±0.013 ml·g-1·min-1）。在血糖正常期间，非糖尿病受试者全脑示踪剂计算的葡萄糖代谢高于糖尿病受试者（22.0±1.9对15.6±1.1 μmol·100 g-1·min-1，P<0.01）。在低血糖期间，非糖尿病受试者示踪剂计算的代谢降低了40%，糖尿病受试者降低了28%。结果表明，一组血糖控制良好的IDDM受试者的葡萄糖摄取正常，但葡萄糖代谢的某些方面存在异常。
