Researchers at the University of Pennsylvania School of Medicine have established in an animal model that the hormone adiponectin secreted by fat tissue acts in the brain to reduce body weight. In contrast to leptin, a related hormone, adiponectin can cause weight loss by raising metabolic rate while not affecting appetite. This finding may have future implications in understanding and treating obesity and metabolic disorders like diabetes, says lead author, Rexford Ahima, MD, PhD, Assistant Professor of Medicine, Penn Diabetes Center. This research appears in the May issue of Nature Medicine.