Influence of diet on glucose metabolism of soleus muscle in artificially-fed 15- and 20-day-old Zucker fatty rats.

The relationship between diet and soleus muscle insulin responsiveness was examined in lean and obese Zucker rat pups that were artificially fed high-fat and high-carbohydrate liquid diets from 10 to 20 d of age and compared to pups that suckled normally. Elevated plasma glucose and insulin concentrations were found in both lean and obese artificially-fed pups at 20 d as compared to dam-fed controls. Total glucose utilization in isolated soleus muscle was estimated from the sum of the rates of 14C-glucose oxidation and 14C-glucose incorporation into glycogen and varied with genotype, age and diet. In general, soleus muscle from artificially-fed obese pups showed a lower basal and insulin-stimulated total glucose utilization than lean pups, with a greater and earlier effect due to high carbohydrate feeding. These results suggest that early dietary modification can alter peripheral target tissue insulin responsiveness and accelerate the onset of the insulin-resistant state.