Lillioja S
University of New South Wales, South Western Sydney Clinical School, Liverpool Health Service, Australia.
Diabet Med. 1996 Sep;13(9 Suppl 6):S127-32.
More than 50% of Pima Indians develop NIDDM. This disorder is preceded by impaired glucose tolerance (IGT) and we tested the hypothesis that the elevated glucose levels in IGT must be due to reduced beta-cell function. We first determined the plasma glucose/plasma insulin and plasma insulin/insulin resistance relationships in individuals with NGT, relationships which by definition must be normal, and determined if these relationships were intact in individuals with IGT. We also compared Pimas and Caucasians with NGT or IGT. Subjects were assessed with an OGTT, an IVGTT, underwater weighing (for body composition), and a euglycaemic clamp. The results showed that insulin concentrations in Pimas with IGT were not lower than the levels predicted by the relationships found in subjects with NGT. Compared to Caucasians, Pima Indians had elevated insulin concentrations at the same degree of insulin resistance. These studies indicate that insulin resistance, and not beta-cell failure, is the principal lesion determining IGT in Pimas. NIDDM occurs when beta-cell failure develops in the presence of insulin resistance. In some individuals of other races, beta-cell function may be less able to withstand insulin resistance, and presumably in these individuals beta-cell failure assumes a greater importance in the evolution to NIDDM.
超过50%的皮马印第安人会患非胰岛素依赖型糖尿病（NIDDM）。这种疾病之前会出现糖耐量受损（IGT），我们检验了这样一个假设，即IGT中血糖水平升高必定是由于β细胞功能降低所致。我们首先确定了糖耐量正常（NGT）个体的血浆葡萄糖/血浆胰岛素以及血浆胰岛素/胰岛素抵抗之间的关系，根据定义这些关系必定是正常的，然后确定这些关系在IGT个体中是否完整。我们还比较了患有NGT或IGT的皮马印第安人和高加索人。通过口服葡萄糖耐量试验（OGTT）、静脉葡萄糖耐量试验（IVGTT）、水下称重法（用于测定身体成分）以及正常血糖钳夹技术对受试者进行评估。结果显示，患有IGT的皮马印第安人的胰岛素浓度并不低于根据NGT受试者中发现的关系所预测的水平。与高加索人相比，皮马印第安人在相同程度的胰岛素抵抗下胰岛素浓度升高。这些研究表明，胰岛素抵抗而非β细胞功能衰竭是决定皮马印第安人IGT的主要病变。当在存在胰岛素抵抗的情况下发生β细胞功能衰竭时，就会出现NIDDM。在其他种族的一些个体中，β细胞功能可能较难耐受胰岛素抵抗，据推测在这些个体中，β细胞功能衰竭在向NIDDM发展过程中起更大作用。
