[Effects of chronic administration of benfluorex on the pharmacokinetics of iodine 123 labelled insulin in Zucker obese rats (fa/fa)].

Zucker obese rats (fa/fa), aged 8 to 10 weeks, were treated orally by benfluorex (2 x 25 mg.kg-1, day-1) for 2 weeks and were compared with a control group of the same age treated with placebo. Benfluorex induced a break in the weight curve, a significant fall in serum triglycerides, blood glucose and plasma insulin and in the insulin content of the pancreas. Following intrajugular injection of iodine 123 labelled insulin, the liver of the treated animals bound 25 percent more insulin than the liver of control animals. Conversely, the renal clearance of insulin of the treated animals was reduced in comparison to the placebo group. These studies confirm that, in an animal model of obesity associated with insulin resistance, benfluorex exerts a marked hypolipidemic effect and improves insulin resistance. They also demonstrate an increased targeting of insulin towards hepatic receptors either due to an increase in the hepatic blood flow or to an increase in the number of hepatic receptors or to an increase in the affinity of these receptors. However, speculative considerations make this last mechanistic hypothesis somewhat improbable.