(IMAGE) Champalimaud Centre for the Unknown Caption During fasting or exercise, immune cells (red) migrate to the pancreas and stimulate glucagon-producing cells (orange) to regulate blood sugar, with cell nuclei shown in blue. Credit Immunophysiology Lab, Champalimaud Foundation Usage Restrictions No restriction License Original 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.