Anemic stress as a trigger of myelogenous leukemia in rats rendered leukemia-prone by x-ray

All of the 128 Sprague-Dawley female rats bled two-thirds of the blood volume at 1, 2, or 3 months after irradiation (50, 170, or 350 roentgens) succumbed to leukemia by 16 months after bleeding. Some nonbled irradiated rats developed leukemia possibly as a result of triggering by a radiation-induced anemia. The threshold leukemogenic x-ray dose is probably below 25 roentgens. Elevated levels of basophils, neutrophils containing the "pseudo-Pelger" type nuclear anomaly, and myeloblasts exhibiting Auer rods seen in these animals were generally not found in earlier models of rat myelogenous leukemia.