In the present study, the rat model of obesity induced by a high fat diet was used to investigate the role played by the hypothalamic excitatory (glutamate and aspartate), and inhibitory (GABA, glycine and taurine) amino acid neurotransmitters and the associated changes in the serum levels of leptin and ghrelin in obesity. This evidence concerns the gene GHRL and obesity due to melanocortin 4 receptor deficiency.