Rigalleau V, Beylot M, Pachiaudi C, Guillot C, Deleris G, Gin H
Service de Nutrition et Diabétologie, Hôpital Haut-Lévêque, 33600 Pessac, France.
Am J Physiol. 1998 Oct;275(4):E641-8. doi: 10.1152/ajpendo.1998.275.4.E641.
Lipid infusions may affect glucose tolerance by effects on glucose production or utilization. We performed double-labeled oral glucose tolerance tests with and without a lipid infusion in eight normal subjects. During the lipid infusion, plasma glucose and insulin levels were higher, showing some insulin resistance. The increased glucose level was due to a higher total glucose appearance rate, partly reproducible by a control infusion of glycerol [saline 1,181 +/- 71 mg . kg-1 . 330 min-1 vs. lipid 1,388 +/- 100 (P < 0.05) vs. glycerol 1,276 +/- 126 (NS)]. The tracer-determined appearance rate of exogenous glucose was higher with lipid infusion but was probably overestimated because of higher 13C recycling into glucose. Residual systemic glucose production was increased but was reproducible by the glycerol infusion. Total glucose disposal was increased. This was observed despite a lower stimulation of total glucose oxidation as measured by indirect calorimetry, whereas oxidation of exogenous glucose was normal after correction for the lipid-induced modification of excretion rate of 13CO2. Accordingly, glucose nonoxidative disposal was increased. These moderate modifications of glucose metabolism (increased appearance, increased nonoxidative disposal, and lower total oxidation) have been reported in starvation-induced or spontaneously impaired glucose tolerance. Further impairment, especially decreased nonoxidative glucose disposal, seems to be required to produce non-insulin-dependent diabetes mellitus.
脂质输注可能通过影响葡萄糖生成或利用来影响葡萄糖耐量。我们对8名正常受试者进行了有无脂质输注的双标记口服葡萄糖耐量试验。在脂质输注期间，血浆葡萄糖和胰岛素水平较高，显示出一定程度的胰岛素抵抗。血糖水平升高是由于总葡萄糖出现率较高，部分可通过甘油对照输注重现[生理盐水1,181±71毫克·千克⁻¹·330分钟⁻¹，脂质组1,388±100（P<0.05），甘油组1,276±126（无显著性差异）]。脂质输注时示踪剂测定的外源性葡萄糖出现率较高，但可能因13C更多地循环回葡萄糖而被高估。残余全身葡萄糖生成增加，但可通过甘油输注重现。总葡萄糖处置增加。尽管通过间接测热法测量的总葡萄糖氧化刺激较低，但仍观察到这一现象，而在校正脂质诱导的13CO2排泄率改变后，外源性葡萄糖氧化正常。因此，葡萄糖非氧化处置增加。饥饿诱导的或自发受损的葡萄糖耐量中曾报道过葡萄糖代谢的这些适度改变（出现增加、非氧化处置增加和总氧化降低）。似乎需要进一步受损，尤其是非氧化葡萄糖处置降低，才能导致非胰岛素依赖型糖尿病。
