Rother K I, Schwenk W F
Department of Pediatrics, Mayo Clinic, Rochester, Minnesota 55905, USA.
Am J Physiol. 1995 Oct;269(4 Pt 1):E774-8. doi: 10.1152/ajpendo.1995.269.4.E774.
Children with glycogen storage disease type I (GSD I) lack the ability to convert glucose 6-phosphate to glucose and yet are able to produce glucose endogenously. To test the hypothesis that the source of this glucose is increased cycling of glucose moieties through hepatic glycogen, six children with GSD I were studied on two occasions during which they received enteral glucose for 6 h at 35 or 50 mumol.kg-1.min-1 along with [6,6-2H2]glucose to measure plasma glucose flux and [1-13C]galactose to label intrahepatic uridyl diphosphate (UDP)-glucose. After 3 h, acetaminophen was given to estimate UDP-glucose flux (reflecting the rate of glycogen synthesis). Mean steady-state plasma glucose concentrations (4.8 +/- 0.2 vs. 5.8 +/- 0.1 mM) and total flux (34.8 +/- 1.7 vs. 47.5 +/- 2.0 mumol.kg-1.min-1) were increased (P < 0.05 or better) on the high-infusion day. Endogenous glucose production was detectable only on the low-infusion day (2.0 +/- 0.5 mumol.kg-1.min-1). UDP-glucose flux was increased (P < 0.05) on the high-infusion day (25.8 +/- 1.6 vs. 34.7 +/- 4.1), ruling out cycling of glucose moieties through glycogen with release of glucose by debrancher enzyme as the source of glucose production.
I型糖原贮积病（GSD I）患儿缺乏将6-磷酸葡萄糖转化为葡萄糖的能力，但仍能够内源性地产生葡萄糖。为了验证这种葡萄糖的来源是通过肝糖原增加葡萄糖部分的循环这一假说，对6名GSD I患儿进行了两次研究，期间他们分别以35或50 μmol·kg⁻¹·min⁻¹的速率接受肠内葡萄糖输注6小时，同时给予[6,6-²H₂]葡萄糖以测量血浆葡萄糖通量，并给予[1-¹³C]半乳糖以标记肝内尿苷二磷酸（UDP）-葡萄糖。3小时后，给予对乙酰氨基酚以估计UDP-葡萄糖通量（反映糖原合成速率）。在高输注日，平均稳态血浆葡萄糖浓度（4.8±0.2对5.8±0.1 mM）和总通量（34.8±1.7对47.5±2.0 μmol·kg⁻¹·min⁻¹）增加（P<0.05或更佳）。仅在低输注日可检测到内源性葡萄糖生成（2.0±0.5 μmol·kg⁻¹·min⁻¹）。在高输注日，UDP-葡萄糖通量增加（P<0.05）（25.8±1.6对34.7±4.1），排除了葡萄糖部分通过糖原循环并由脱支酶释放葡萄糖作为葡萄糖生成来源的可能性。
