Very low density lipoprotein metabolism in non-ketotic diabetes mellitus: Effect of dietary restriction

We have measured the turnover of very low density lipoprotein (VLDL) triglyceride as well as plasma glucose, insulin and non-esterified fatty acid levels in nine mildly obese non-ketotic, insulinopenic diabetic subjects before and during an energy restricted diet. During the baseline period, subjects were hypertriglyceridaemic, hyperglycaemic and insulinopenic. During dietary restriction (mean weight loss: 2.3±0.4 kg) plasma triglyceride fell from 8.4±3.0 to 3.4±0.89 mmol/l (mean±SEM; p<0.05), and plasma glucose fell from 13.9 ±1.7 to 9.8±1.4 mmol/l (p<0.01). Neither fasting plasma insulin nor the insulin response to an oral glucose load changed. Plasma non-esterified fatty acid concentrations remained constant as well. During the baseline period, the transport rate of VLDL-triglyceride in the diabetic subjects was more than twice that in an age-weighted matched control group (27.4±2.9 versus 12.1±0.8 mg/kg ideal body weight per h). The fractional catabolic rates were similar in the two groups (0.20±0.05 versus 0.21±0.02/h). During energy restriction of the diabetic subjects, the VLDL-triglyceride transport rate fell to 17.4±2.9 mg/kg ideal body weight per h (p<0.05 versus baseline) while the fractional catabolic rate remained constant at 0.21±0.06/h (NS versus baseline). These data indicate that the major abnormality in triglyceride metabolism in these non-ketotic, insulinopenic diabetic patients was over-production of VLDL-triglyceride.