NAD Relay (IMAGE) University of Pennsylvania School of Medicine Caption This image shows enzymes in the NAD salvage pathway 'handing off' molecules to the front runner, representing fully formed NAD leading the pack in terms of muscle function. Credit Artwork by Mary Leonard and courtesy of Joe Baur, Perelman School of Medicine, University of Pennsylvania and Cell Press. 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.