Castilho E M, Glass M L, Manço J C
Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
Braz J Med Biol Res. 2003 Jun;36(6):731-7. doi: 10.1590/s0100-879x2003000600008. Epub 2003 Jun 3.
The position of the oxygen dissociation curve (ODC) is modulated by 2,3-diphosphoglycerate (2,3-DPG). Decreases in 2,3-DPG concentration within the red cell shift the curve to the left, whereas increases in concentration cause a shift to the right of the ODC. Some earlier studies on diabetic patients have reported that insulin treatment may reduce the red cell concentrations of 2,3-DPG, causing a shift of the ODC to the left, but the reports are contradictory. Three groups were compared in the present study: 1) nondiabetic control individuals (N = 19); 2) insulin-dependent diabetes mellitus (IDDM) patients (on insulin treatment) (N = 19); 3) non-insulin-dependent diabetes mellitus (NIDDM) patients using oral hypoglycemic agents and no insulin treatment (N = 22). The overall position of the ODC was the same for the three groups despite an increase of the glycosylated hemoglobin fraction that was expected to shift the ODC to the left in both groups of diabetic patients (HbA1c: control, 4.6%; IDDM, 10.5%; NIDDM, 9.0%). In IDDM patients, the effect of the glycosylated hemoglobin fraction on the position of the ODC appeared to be counterbalanced by small though statistically significant increases in 2,3-DPG concentration from 2.05 (control) to 2.45 mol/ml blood (IDDM). Though not statistically significant, an increase of 2,3-DPG also occurred in NIDDM patients, while red cell ATP levels were the same for all groups. The positions of the ODC were the same for control subjects, IDDM and NIDDM patients. Thus, the PO2 at 50% hemoglobin-oxygen saturation was 26.8, 28.2 and 28.5 mmHg for control, IDDM and NIDDM, respectively. In conclusion, our data question the idea of adverse side effects of insulin treatment on oxygen transport. In other words, the shift to the left reported by others to be caused by insulin treatment was not detected.
氧解离曲线（ODC）的位置受2,3 - 二磷酸甘油酸（2,3 - DPG）调节。红细胞内2,3 - DPG浓度降低会使曲线左移，而浓度升高则导致ODC右移。一些早期针对糖尿病患者的研究报告称，胰岛素治疗可能会降低红细胞中2,3 - DPG的浓度，导致ODC左移，但这些报告相互矛盾。本研究比较了三组：1）非糖尿病对照个体（N = 19）；2）胰岛素依赖型糖尿病（IDDM）患者（接受胰岛素治疗）（N = 19）；3）使用口服降糖药且未接受胰岛素治疗的非胰岛素依赖型糖尿病（NIDDM）患者（N = 22）。尽管两组糖尿病患者糖化血红蛋白比例升高，预计会使ODC左移（糖化血红蛋白：对照组4.6%；IDDM组10.5%；NIDDM组9.0%），但三组的ODC总体位置相同。在IDDM患者中，糖化血红蛋白比例对ODC位置的影响似乎被2,3 - DPG浓度虽小但具有统计学意义的升高所抵消，2,3 - DPG浓度从2.05（对照组）升至2.45 μmol/ml血液（IDDM组）。NIDDM患者中2,3 - DPG也有升高，虽无统计学意义，而所有组的红细胞ATP水平相同。对照组、IDDM和NIDDM患者的ODC位置相同。因此，血红蛋白氧饱和度为50%时的氧分压，对照组、IDDM和NIDDM分别为26.8、28.2和28.5 mmHg。总之，我们的数据对胰岛素治疗对氧运输有不良副作用这一观点提出质疑。换句话说，未检测到其他人所报告的由胰岛素治疗引起的曲线左移。
