Catecholamines are a group of similar hormones produced in the adrenal medulla that are released into the bloodstream in response to physical or emotional stress, such as, elevated sound levels, intense light, or low blood sugar levels. The primary catecholamines are dopamine, adrenaline (epinephrine), and noradrenaline (norepinephrine). They help transmit nerve impulses in the brain, increase glucose and fatty acid release for energy, dilate bronchioles, and dilate the pupils. Noradrenaline also constricts blood vessels, increasing blood pressure, and adrenaline increases heart rate and metabolism. After completing their actions, the hormones are metabolized into inactive compounds, and both the hormones and their metabolites are excreted in the urine. Catecholamine testing is primarily used to help detect and rule out pheochromocytomas in symptomatic patients, which is a catecholamine-secreting tumor of chromaffin cells typically located in the adrenals and causes persistent or paroxysmal hypertension. It also may be ordered to help monitor the effectiveness of treatment when a pheocromocytoma is discovered and removed, and to monitor for recurrence. INCREASED levels of catecholamines are associated with pheochromocytomas, and other neuroendocrine tumors. Symptoms may include hypertension, severe headaches, palpitations, sweating, nausea, anxiety, and tingling in the extremities.