About 50% of adrenal pheochromocytomas produce near exclusively norepinephrine, this representing the same pattern as in extra-adrenal pheochromocytomas.
Production of epinephrine (best detected by an increase in metanephrine) indicates an adrenal location,
exclusive production of norepinephrine (best indicated by increases of normetanephrine with normal metanephrine) may reflect either an adrenal or extra-adrenal location.
Practically all epinephrine-producing pheochromocytomas are found in the adrenal gland or are recurrences of previously resected adrenal tumors.
All of the catecholamines are broken down into inactive substances that appear in the urine:
Production of epinephrine (best detected by an increase in metanephrine) indicates an adrenal location,
exclusive production of norepinephrine (best indicated by increases of normetanephrine with normal metanephrine) may reflect either an adrenal or extra-adrenal location.
Practically all epinephrine-producing pheochromocytomas are found in the adrenal gland or are recurrences of previously resected adrenal tumors.
All of the catecholamines are broken down into inactive substances that appear in the urine:
- Dopamine becomes Homovanillic acid (HVA)
- Norepinephrine becomes normetanephrine and vanillylmandelic acid (VMA)
- Epinephrine becomes metanephrine and VMA
| Effect | Epinephrine | Norepinephrine |
| Heart rate | increases | decreases |
| Cardiac output | increases | variable |
| Blood pressure | increases | increases |
| Respiration | increases | increases |
| Metabolism | increases | small increase |
| Behavior | passive, tense | aggressive |
| Eosinophil count | increases | ---- |
| Skin blood vessels | dilate | constrict |
| Muscle blood vessels | dilate | small dilation |
