Effect of dietary fructose on triglyceride turnover in streptozotocin-diabetic rats

The effects of fructose or glucose on plasma triglyceride kinetics in streptozotocin (40 mg/kg) diabetic rats were studied using Triton WR1339. To separate groups of diabetic rats fructose or glucose was supplied at 10% in drinking water. Diabetic rats without sugar supplementation (diabetic control) had significantly suppressed triglyceride secretion compared to non-diabetic controls. Neither fructose nor glucose supplementation increased the triglyceride secretion rate in diabetic rats. However, despite reduced secretion rates, plasma triglyceride levels in glucose-supplemented diabetic rats, diabetic controls and non-diabetic controls were essentially identical. This suggested that removal of triglyceride from the circulation was impaired in the diabetic rats. In contrast, fructose supplementation resulted in a more than 150% (significant) increase in the mean plasma triglyceride of diabetic rats. The observation of significant hypertriglyceridemia in spite of low triglyceride secretion rate in fructose-supplemented diabetic rats suggests that dietary fructose, but not glucose, interferes with triglyceride removal from the circulation of streptozotocin-diabetic rats. This impairment by dietary fructose is in addition to the impaired triglyceride removal associated with diabetes alone.