Palatable High Fat Diet Modifies the Adipose Tissue Metabolism in Rats with Respect to the Age and the Treatment Time

We have previously shown that the continuous intake of a palatable hyperlipidic diet (H) or alternate cycles of the standard diet (C) and H diets (CH diet) induced obesity in rats. In this study we investigate the relevance of the animal's age and duration of treatment with these diets on glucose metabolism in isolated adipocytes and adiponectin gene expression and leptin receptors density. Male Wistar rats received C, H, or CH diets, during 3 different periods: from 30 to 60; from 30 to 90 or from 60 to 90 days old. The diameter, the area and volume of the isolated adipocytes from retroperitoneal adipose tissue (RET) increased in H and CH (30-60 and 30-90); and from epididymal adipose tissue (EPI) in H and CH (30-90). The glucose incorporation rate in lipids was higher in isolated adipocytes RET of all animals treated with CH diet, as well as in EPI from H30-90 and CH60-90. Adipocytes of RET in H30-90, CH30-90, CH60-90 and CH30-60 groups and of EPI in H and CH (30-90) and CH60-90 groups, observe an increase of CO2 glucose oxidation rate into CO2. The leptin receptor density increased in RET of H and CH (30-60) groups and in EPI of CH30-90. Serum triacylglycerol level increased in all CH groups. These findings showed that the intake H and CH diets cause hypertrophy of adipocytes and depend on treatment time, animal age and the type of fat deposit. Moreover, may have atherogenic effect by inhibiting the gene expression of adiponectin.