THE EFFECT OF TOXOHORMONE ON IRON METABOLISM TETSUO ONO, MOCHIHIKO OHASHI and NAGASUMI YAGO (Cancer Institute, Japanese Foundation for Cancer Research, Tokyo) Fukuoka and Nakahara postulated that the role of toxohormone in depressing liver catalase activity may be to disturb the iron metabolism, based on their finding that either the feeding of dried liver, blood powder or iron or the simultaneous injection of iron with toxohormone were capable of counteracting the catalase depressing action in

more »

... vivo (3). In the course of the experiments to elucidate the mechanism of catalase depression in tumor-bearing animals, the authors observed the accumulation of free protoporphyrin in the blood and liver of these animals. A porphyric state was also produced by the injection of toxohormone (8). These findings were considered to support the hypothesis that the heme synthesis in the tumor-bearing animals is impaired at the step of iron insertion into protoporphyrin rings. This hypothesis was further strengthened by the iron administration experiments, in which a large dose of iron in the diet completely prevented the porphyrin accumulation and the iron administration combined with cobalt corrected completely the amemia of tumor-bearing animals (4, 9). Besides the catalase depression and anemia, there are other symptoms indiating the disturbance of iron metabolism in tumor-bearing animals, such as the decrease of plasma iron as well as of the liver ferritin content (10). The latter symptom was also attributed to the action of toxohormone from the malignant tumor by the experiment of Mizuhara et al. (6). Recently Kampschmidt et al. ( 5 ) reexamined the systemic effect of toxohormone