A Fat Cell Grows Up (IMAGE) University of Pennsylvania School of Medicine Caption This is a mature fat cell. Credit Mitchell A. Lazar, M.D., Ph.D., University of Pennsylvania School of Medicine Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.