Comparative Metabolism of Phosphorus in Normal and Lymphomatous Animals. ∗

Abstract

When radioactive phosphorus is fed to normal rats, mice or chickens 1-4 in an ordinary diet, a large percentage of the phosphorus is deposited in the bony skeleton. This more or less selective deposition of phosphorus in bone, suggested to us the possibility of using radioactive phosphorus as a source of therapeutic irradiation in leukemia. In preliminary experiments, mice with lymphatic and myelogenous leukemia were fed radiophosphorus in relatively small amounts and there was no definite influence on the course of the disease. However, at autopsy, some of the tissues were assayed for activity and it was unexpectedly found that in leukemia there is an abnormality in the handling of a single dose of tagged phosphorus. Before pursuing this question further, it seemed to us important to determine first the total phosphorus content of leukemic, lymphomatous and normal tissues as a basis for further study. The findings 5 show that per gram wet weight, lymphomatous tissue or tissues infiltrated with lymphoid cells have no greater total phosphorus content than their normal analogues, i. e., lymph glands and various uninfiltrated viscera. We wish here to report observations on normal and lymphomatous mice which show that a single dose of phosphorus is handled differently in the latter group of animals.

The phosphorus used in these experiments was made radioactive in the cyclotron of Lawrence and Cooksey 6 by bombarding red phosphorus with deuterons having an energy of approximately eight million volts. As stated above, P³², the radioactive isotope, is chemically similar to P³¹, the naturally occurring element. It has a half life of about 14.8 days. Because of the beta ray emission, radio-phosphorus can be detected and quantitated by means of an electroscope or a Geiger counter.