Catecholamines are produced in chromaffin cells in the medulla of the adrenal gland, from tyrosine , a non-essential amino acid derived from food or produced from phenylalanine in the liver. The enzyme tyrosine hydroxylase converts tyrosine to L-DOPA in the first step of catecholamine synthesis. L-DOPA is then converted to dopamine before it can be turned into noradrenaline. In the cytosol , noradrenaline is converted to epinephrine by the enzyme phenylethanolamine N-methyltransferase (PNMT) and stored in granules. Glucocorticoids produced in the adrenal cortex stimulate the synthesis of catecholamines by increasing the levels of tyrosine hydroxylase and PNMT.  
Pheochromocytoma is a neoplasm composed of cells similar to the chromaffin cells of the mature adrenal medulla. Pheochromocytomas occur in patients of all ages, and may be sporadic, or associated with a hereditary cancer syndrome , such as multiple endocrine neoplasia (MEN) types IIA and IIB, neurofibromatosis type I, or von Hippel-Lindau syndrome . Only 10% of adrenal pheochromocytomas are malignant , while the rest are benign tumors . The most clinically important feature of pheochromocytomas is their tendency to produce large amounts of the catecholamine hormones epinephrine (adrenaline) and norepinephrine . This may lead to potentially life-threatening high blood pressure , or cardiac arrythmias , and numerous symptoms such as headache , palpitations , anxiety attacks , sweating , weight loss , and tremor . Diagnosis is most easily confirmed through urinary measurement of catecholamine metabolites such as VMA and metanephrines . Most pheochromocytomas are initially treated with anti-adrenergic drugs to protect against catecholamine overload, with surgery employed to remove the tumor once the patient is medically stable.
Even your propensity to develop certain kinds of diseases and your ability to respond to chronic illness is influenced significantly by the adrenal glands. The more chronic the illness, the more critical the adrenal response becomes. You cannot live without your adrenal hormones and, as you can see from this very brief overview, how well you live depends a great deal on how well your adrenal glands function. For a more detailed explanation of adrenal function, please refer to Dr. Wilson’s book: ”Adrenal Fatigue: the 21st Century Stress Syndrome”, and read Chapter 22: “Anatomy and Physiology of the Adrenal Glands”.