DIETARY FRUCTOSE ALTERS THE INSULIN-LIKE EFFECTS OF DIETARY VANADATE IN ADIPOCYTES FROM RATS

In a chronic adaption feeding regimen, both D-fructose and vanadate in dependently altered glucose oxidation and lipogenesis in adipose tissu e of rats. This study investigated the acute feeding effects of vanada te and D-fructose on these parameters in isolated rat adipocytes. In a 3-d fasting/refeeding regimen, male Wistar rats (10/group), weighing 150-200 g, were fed a diet containing either glucose (control) or fruc tose at 27% (w/w) with sodium orthovanadate at 0, 25 (vanadate-l), and 50 (vanadate-2) mg/kg of diet. Neither body weight gain nor food effi ciency differed statistically between treatment groups, but lower food intake in vanadate-treated animals suggests a compensatory effect of food efficiency in maintaining body weight gain at the same level as i n other groups. Basal glucose oxidation to CO2 was enhanced in a dose- related fashion in glucose-vanadate groups, but a significant interact ion between fructose and vanadate led to a reduction in vanadate-induc ed basal glucose oxidation. The reduction in basal and insulin-stimula ted glucose conversion to lipid in adipocytes and in hepatic glucose 6 -phosphate dehydrogenase and malic enzyme activities by vanadate was n ot altered by fructose. These results suggest that, under acute feedin g, fructose alters the insulin-mimetic aspect of vanadate involving gl ucose conversion to CO2 in isolated adipocytes.