Carcinoid Tumors
Serotonin is a hormone responsible for feelings of happiness. In excess, however, it can cause sweating, shaking, diarrhea, and a wide variety of unpleasant symptoms. Carcinoid tumors are tumors of the digestive tract, including the pancreas, that produce serotonin. The liver can quickly remove large amounts of serotonin from the bloodstream, so this tumor often is not discovered until it has metastasized or grown extremely large.
