The comparison of daily injection of recombinant leptin protein (rh-leptin) and adenovirus-mediated delivery of the murine or human leptin gene (Ad-leptin) for treatment of obesity in the ob/ob mouse model reveals that the rate of weight loss and the percentage satiety were significantly higher in the mice treated with Ad-leptin (Morsy et al., 1998). This evidence concerns the gene LEP and obesity due to melanocortin 4 receptor deficiency.