A Zucker rat bred as a genetic model for
obesity. Photo courtesy of Joanna Servaes
Obesity and diabetes have become serious health concerns throughout the world. Diabetes arises from a malfunction in glucose metabolism. The body is unable to make or cannot properly respond to insulin—a hormone released from the pancreas that takes glucose from the blood and moves it into cells to be used as energy. When cells fail to respond properly to insulin, glucose begins to build up in the blood and complications, such as kidney disease and high blood pressure, develop.
Obesity occurs when the body is unable to metabolize calories at the rate that they are consumed. Obesity, a term used to describe people with a body mass index (BMI) over 30 is generally caused by consuming too many calories and not burning enough through exercise, although genetics is a factor too. The condition often is treated with a diet and exercise regimen, but medical and surgical options are used as well. (To find a weight management solution, visit the Johns Hopkins Weight Management Center for more information.)
Scientists at the Johns Hopkins IBBS Center for Metabolism and Obesity Research are working on not only on improving our understanding of metabolism, but also on learning about what goes wrong in diabetes and obesity, so that they can develop better therapies.
Gabriele Ronnett, professor of neuroscience and the director of the Center for Metabolism and Obesity Research, studies how the brain senses nutrients and hormones and translates these signals into behaviors such as exercising or abstaining from eating when full. She compares how the neurons in the brain respond in thin animals versus animals that are predisposed to obesity to determine on a molecular level how regulation of behavior is lost in animals with obesity. Her lab is using this information to develop potential drug candidates that alter fat metabolism and help enable weight loss.
Michael Wolfgang and his colleagues in the Department of Biological Chemistry study the role of metabolites in controlling food uptake, energy expenditure and body weight. Specifically, Wolfgang’s lab focuses on the way neurons sense and respond to the nutrients available in the body. He hopes to identify and better understand the metabolic enzymes present in neurons to someday develop new approaches to controlling diabetes and obesity.
The DeLamar Professor and director of the Department of Biological chemistry, Gerald Hart, studies the effects of high blood sugar, which occurs in people with untreated diabetes. Sugar that isn’t transferred into cells by insulin to be used as an energy source becomes transformed into a special type of sugar and gets attached to different proteins and changes how they behave. Hart's work explains why high sugar is toxic. Also, he has developed a way to detect prediabetes by the presence of certain sugar molecules on a protein found in blood cells. This technique may develop into a diagnostic test for patients who are at risk for diabetes.