In humans, the relative long-term constancy of body weight, the difficulty of successfully
sustaining intentional weight loss, and the metabolic and behavioral alterations that
accompany weight change provide strong evidence that body fat is biologically regulated. 1
The amount of energy stored as fat affects growth, puberty, fertility, and thyroid function,
which suggests that humoral signals reflecting adipose-tissue mass interact with many
neuroendocrine systems. 1 In mice, the products of the ob and db genes are the main …

This review focuses on current knowledge of leptin biology and the role of leptin in various
physiological and pathophysiological states. Leptin is involved in the regulation of body
weight. Serum leptin can probably be considered as one of the best biological markers
reflecting total body fat in both animals and humans. Obesity in man is accompanied by
increased circulating leptin concentrations. Gender differences clearly exist. Leptin is not
only correlated to a series of endocrine parameters such as insulin, glucocorticoids, thyroid …