Ten subjects with obesity and diabetes (OD), 11 with obesity alone (O), and 11 normal-weight controls (C) – males, aged 26–59 years, with fasting normo-triglyceridaemia underwent measurements of cholesterol, triglycerides, apo B-48 and apo B-100 concentrations in plasma lipoproteins separated by density gradient ultracentrifugation before and after a fat-rich meal. Fasting and postprandial (6 h) LPL activity was determined in abdominal subcutaneous adipose tissue biopsy samples. Insulin sensitivity was measured by hyperinsulinaemic euglycaemic clamp. OD and O subjects had similar degrees of adiposity (BMI, waist circumference, fat mass) and insulin resistance (insulin stimulated glucose disposal and M/I). They also showed a similarly higher postprandial increase in large VLDL lipids (triglyceride incremental AUC 188 ± 28 and 135 ± 22 mg/dl·6 h) than C (87 ± 13 mg/dl·6 h, M ± SEM, p < 0.05). OD had an increased chylomicron response compared to O (triglyceride incremental AUC 132 ± 23 vs. 75 ± 14 mg/dl·6 h, p < 0.05). OD had significantly lower fasting and postprandial adipose tissue heparin-releasable LPL activity than O and C.
In insulin-resistant conditions of obesity, with and without diabetes, large VLDL are increased after a fat-rich meal. In addition, diabetic patients compared to obese subjects have an increased postprandial chylomicron response and a reduced adipose tissue LPL activity.