Pheochromocytoma in rats: incidence, etiology, morphology and functional activity.

The incidence of spontaneous pheochromocytoma in rats varies with the strain, sex, age and diet of the animals. Treatment with growth hormone, estrogens, or radiation is associated with the occurrence of pheochromocytoma in the rat. Histological evidence and transplantation studies indicate that pheochromocytoma in rats possesses a low grade of malignancy. A transplantable radiation-induced pheochromocytoma model has been shown to be functionally active.