Scientists are reporting new evidence that the fat tissue in those lower belly pooches -- far from being a dormant storage depot for surplus calories -- is an active organ that sends chemical signals to other parts of the body, perhaps increasing the risk of heart attacks, cancer, and other diseases. They are reporting discovery of 20 new hormones and other substances not previously known to be secreted into the blood by human fat cells and verification that fat secretes dozens of hormones and other chemical messengers.