Previous studies have demonstrated that a lard high-fat diet induces obesity and resistance to insulin and leptin. Because insulin and leptin can modulate the activity of AMPK, the aim of the present work was to compare the effects of a lard high-fat or a fish-oil high-fat diet on the expression of AMPK-1a in the hypothalamus. 4 groups of 4 rats each were fed with high fat diet or standard diet for 1, 2, 3 or 6 weeks; one group of 4 rats was fed with fish oil for 6 weeks. At the end of the treatment, the expression of AMPK-1a- and p-AMPK-1a-protein were evaluated by conventional Western blot.

The results showed a significant increase in body weight of animals fed with lard high-fat diet compared to fish oil high-fat diet fed rats or standard diet fed rats. pAMPK-1a was increased only at 6 weeks after the lard high-fat diet; no modification of pAMPK-1a was seen in any the other group compared to standard died fed rats. These data indicate that the lard high-fat diet can affect the AMPK activity in the hyphotalamus. Because a lard high-fat diet, but not a fish-oil high-fat diet, can induce leptin and insulin resistance, it can be argued that leptin or insulin resistance could be involved in the disregulation of AMPK in the hyphotalamus.