Comparative Biochemistry of Three Transplantable Mammary Tumors as Influenced by Steroid Therapy23

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Abstract
The effect of steroid administration on certain biochemical components of 3 transplantable mammary tumors in the Fischer rat was investigated. As the dose of diethylstilbestrol was increased in animals bearing the responsive R3230-S tumor, the nitrogen content, the ribonucleic acid/deoxyribonucleic acid (RNA/DNA) ratios, RNA, and acid and alkaline phosphatase activities increased significantly. In animals bearing the less responsive R3230 tumor, diethylstilbestrol treatment slightly increased the RNA/DNA ratios and caused a dose-response increase in acid phosphatase activity. None of these endpoints were changed by estrogen treatment in the unresponsive HMC tumor. Treatment with testosterone propionate slightly increased RNA/DNA ratios in the R3230-S and R3230 tumors. Both acid and alkaline phosphatase activity rose in the R3230-S tumor and the acid phosphatase activity increased in the R3230 tumor. There was no change in the HMC tumor-bearing animals. Although certain alterations of adenosinetriphosphatase and 5′-nucleotidase activities were observed, these changes did not follow any definite pattern, or response to dose. The intracellular distribution of these enzymes was similar in the 3 tumors, but the 5′-nucleotidase activity of the HMC tumor was 5 to 10 times higher than that of the other tumors. A screening protocol, based on steroid-induced alterations of the RNA/DNA ratio in the R3230-S tumor, was adopted and preliminary results of the effect of several steroid and carcinolytic agents are reported.

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