Diabetes is growing into one the biggest health problems in the world and is now responsible for nearly 4 million deaths a year. A team of researchers studied the role of the hormone serotonin, which is stored in the pancreas along with insulin, to see if its absence had any effect on insulin production. Their results showed that the absence of serotonin in the pancreas of mice led to their rapidly developing diabetes. The results, published in the journal Public Library of Science (PLoS) Biology, offer a promising new direction in diabetes