[Obesity etiology: role of leptin]

A huge interest in the scientific community has been aroused since leptin's discovery (from greek leptos=thin), due to its important role in the body energetic balance regulation. This protein is synthesized from ob gene and secreted by the adipose tissue when fat mass increases, decreasing hunger and increasing energy expenditure in order to restore energetic balance. In the latest years many human genetic studies have been conducted showing that sometimes obesity may be due to mutations of genes involved in energetic balance mediated by leptin. These findings amplified the knowledge of obesity etiopathogenesis, thus arousing hopes and expectations for new therapeutic horizons in this disease. Latest researches also outlined many other functions of leptin, some of which are presented in this review. In this paper we collected the most significant data about leptin's physiology and its role in body energetic homeostasis, looking also to the effects on hypothalamus-hypophysis-endocrine axes regulation, on body thermoregulation, on the reproductive function and on foetus and child growth. A wide section is thus reserved to the most recent findings about the role of leptin in obesity and about its therapeutic applications in this field.