[Leptin: physiological and clinical role].

Leptin is a protein that has been identified three years ago, but its role, or at least its deficiency, was suspected from 1950. Dickie and coworkers reported the appearance of a mutant rat in one of their colonies with morbid obesity. The genetic defect was autosomal recessive and was manifested early in life. In December 1994, the gen ob was cloned, which stated the first step for the later identification of the gen product leptin, as a protein of 167 aminoacids expressed in adipose tissue. Since then, leptin has been implicated in many neuroendocrine regulatory pathways. The recent research in leptin roles worth an update review, and so its current and future clinical relevance.