"In addition to its effect on the hypothalamus, leptin acts directly on --
-- The cells of the liver and skeletal muscle where it stimulates the oxidation of fatty acids in the mitochondria. This reduces the storage of fat in those tissues (but not in adipose tissue).
-- T cells where it enhances the production of Th1 cells promoting inflammation. Mice without leptin are protected from autoimmune disease (which may account for the reports that restricting food intake helps humans with Rheumatoid Arthritis )."