Study of Affinity for a Malignant Tumor of Mercuric Compounds (First Report)

Abstract

Three preparations of ²⁰³Hg-acetate, ²⁰³Hg-chlormerodrin and ²⁰³Hg-EDTA were injected intravenously to each group of rats transplanted subcutaneously with Yoshida sarcoma. These rats were sacrificed 3 hours, 12 hours, 48 hours and 72 hours after injection of ²⁰³Hg-acetate and ²⁰³Hg-chlormerodrin and were sacrificed 3 hours, 24 hours and 48 hours after injection of ²⁰³Hg-EDTA. The radioactivities of tumor, blood, muscle, liver, kidney, lung and spleen were measured by a well-type scintillation counter, and retention value in every tissue including tumor was calculated (in per cent of administered dose per g-tissue weight) .
The binding capacity of these mercuric compounds to protein is strong, and retention value of these compounds in the tumor was nearly in proportion to the binding capacity to protein.
The decrease of retention values as time elapsed was the slowest in tumor tissue among principal organs, except the kidney.
It is important for the purpose of clinical scanning that the ratio of the concentration of radioactivity in tumor to tissue is large. Especially concerning the concentration ratio between tumor and muscle, ²⁰³Hg-chlormerodrin, which had the weakest binding capacity to protein in comparison with other mercuric compounds investigated, showed the highest value; that is, ²⁰³Hg-chlormerodrin should be most useful for tumor detection.