Biochemical Studies in Advancing and Re- gressing Rat Mammary Carcinomas Induced by 7,12.Dimethylbenz[a]anthracene (Hug- gins Tumors)l

SUMMARY-The activities of aspartate transcarbamylase (ATC) and phosphoglucomutase (PGM) and the contents of RNA, DNA, and protein were estimated in rat mammary carcinomas (Huggins) induced by 7,12-dimethylbenzlalanthracene. The growth of these tumors could be inAuenced by testosterone administration or ovariectomy. Advancing carcinomas showed high A TC levels and high RNA-DNA ratios. Regressing carcinomas had low A TC levels and low RNA-DNA ratios. The activity of PGM did not correlate with tumor growth rate; it was decreased by testosterone administration. By repeated biochemical analyses of tissue specimens taken serially from the same carcinoma, it was possible to follow directly some of the metabolic changes linked with the hormonally induced growth rate alterations in experimental mammary tumors.-J Nat Cancer Inst 45: 1-10,1970. TUMORS OF the secondary sexual organs differ in many respects from those of other organs