Abnormal composition of apoproteins C-I, C-II, and C-III in plasma and very-low-density lipoproteins of non-insulin-dependent diabetic Chinese.

Apoprotein (apo) C-I, C-II, and C-III were measured in plasma from 35 white American non-diabetic subjects. The mean concentrations (mg/L) in plasma from normolipidemic and hypertriglyceridemic subjects, respectively, were apo C-I, 78 and 311; apo C-II, 37 and 200; and apo C-III, 98 and 529. These concentrations were strongly correlated with the concentrations of plasma triglyceride (TG). We also measured these apoproteins in 23 Chinese non-insulin-dependent diabetic patients (13 men, 10 women) and in eight male and 10 female non-diabetic Chinese controls. The male diabetics had significantly lower concentrations of apo C-I in plasma, and lower apo C-I/TG, apo C-II/TG, apo C-III/TG, and apo C-I/C-III ratios than did the controls. The female diabetics had significantly higher apo C-II concentrations than the controls. The median value for plasma glucose during fasting was 1400 mg/L in the male diabetic subjects, similar to the 1370 mg/L value in female diabetics. Therefore, the higher concentrations of very-low-density lipoprotein in male diabetics may not reflect hyperglycemia per se.