CENTRAL ILLUSTRATION.

Effects of Leptin on Metabolism

Leptin demonstrates metabolic effects that are inversely associated with its circulating levels. In conditions ofabsolute Leptin deficiency, Leptin treatment is highly effective, whereas its efficacy is progressively diminished by increasing leptin levels, probably due to tolerance or resistance to its functions. CLD = congenital leptin deficiency; GL = generalized lipodystrophy; HALS = human immunodeficiency virus-associated lipodystrophy syndrome; PL = partial lipodystrophy.