Aim To understand whether abnormality of lipoprotein in endogenous hypertriglyceridemia (HTG) is associated with insulin resistance, we studied oral glucose tolerance test, insulin secretion, plasma triglyceride (TG) , total cholesterol (TC) , high density lipoprotein cholesterol (HDLC) ,low density lipoprotein cholesterol (LDLC) , apolipoprotein (apo) A Ⅰ ,A Ⅱ ,B100, CⅢ,C Ⅲ and E levels in 53 endogenous HTG patients whose plasma TG levels were ≥2. 26 mmol/L, TC<6. 21mmol/L, and in 33 normal subjects whose plasma lipid levels were normal (TG<2. 26 mmol/L, TC<6. 21mmol/L ).Methods Oral glucose tolerance test and insulin release test were performed by routine methods. Plasma glucose and lipids were determined by enzyme method.Plasma apolipoproteins and insulin were determined respectively by radial immunodiffusion (RID) assay and radio-immunoassay (RIA). Insulin resistance and β-cell function were analysised according to patient's fasting plasma insulin and glucose concentration by Mathews's method.Results The results indicated that the fasting plas ma TG, apo C Ⅱ, CⅢ and E levels were significantlyhigher and HDLC level was lower in the endogenous HTG group than those in the control group (P<0.01). The fasting plasma insulin and glucose levels were normal , but the plasma glucose and insulin levels after glucose loading were increased (P<0.05) and the plasma glucose level at 120 minutes after oral glucose was>7. 22 mmol/L , and the plasma insulin level at 180 minutes after oral glucase was much higher than that in the fasting state (P< 0. 001 ) in the endogenous HTG,while the plasma glucose, the plasma insulin area , the ratio of insulin area to glucose area and the insulin resistance were also increatal in the endogenous HTG group (PM0. 05 ) .Conclusions The results above suggest that the glucose intolerance, the insulin resistance and the hyperinsulinemia existed in the endogenous HTG.