Dietary influence on the insulin function in the epididymal fat cell of the Wistar rat. III. Effect of the ratio carbohydrate to fat.

Newly weaned male Wistar rats were fed semipurified diets containing sunflowerseed oil or palm oil. The fatty acid compositions of the phospholipid and triacylglycerol fractions either from whole epididymal fat pads or from fat cells isolated from the pads appeared to be nearly similar. Feeding the diets for a period of only 3-4 weeks after weaning was found to be sufficient to produce a difference in insulin response and insulin binding in the epididymal fat cells. A reduction in the dietary fat content from 30 to 15% of the energy had only minor effects on fat pad weight and on the fatty acid composition of the phospholipid- and triacylglycerol fractions isolated from the epididymal fat pads. There was no effect either on body weights or on average fat cell diameter but there was an increase in insulin response in the isolated fat cells, however. The difference in insulin response after a diet rich in polyunsaturated fatty acids (sunflowerseed oil) as compared to one rich in saturated fatty acids (palm oil) remained after the reduction of fat content.