Hormonal control of weight loss

Obesity today is the most common cause of poor quality of life in the United States. For the first time since the 1930s, scientists predict that life expectancy in the United States will decline as a result of this epidemic. In 1994, biochemists identified a hormone called leptin that is involved in a positive feedback mechanism with the brain to promote weight loss. Leptin is a $167$‍ amino acid molecule that is secreted by adipose tissue that binds receptors in the brain to stimulate satiety and promote weight loss. A scientist studying the biochemical mechanisms driving obesity is interested in the effect leptin has on weight management and how it communicates with other hormones in the body. She is interested in the effect leptin has on certain parts of the brain. In Table 1, the scientist has knocked out certain parts of the brain believed to be related to the regulation of satiety and appetite.