Metabolism of Mammary-Gland Slices From Rats Receiving Progesterone and 3-Methylcholanthrene2

Abstract

Administration of 3-methylcholanthrene orally for as long as 62 days to young female albino rats receiving progesterone had no demonstrable effect, even in the presence of induced cancers elsewhere in the breast, on the values for the following metabolic parameters of mammary-gland slices: respiration, aerobic glycolysis, anaerobic glycolysis, and catalase activity, as compared to values obtained from control animals receiving either no treatment or sesame oil alone. Progesterone by itself, however, induced proliferation of mammary epithelium and the accompanying increase in QO₂ was due to this proliferation, but after a peak was reached, the epithelium and respiration decreased to the level of controls. When 3-methylcholanthrene was administered with progesterone, the QO₂ did not increase because the epithelium failed to proliferate. Liver slices from animals treated with progesterone alone had an increased and labile QO₂, an effect which was not observed in slices from animals receiving 3-methylcholanthrene in addition to progesterone. Livers from animals receiving 3-methylcholanthrene had an increased lipide content. Treatment of the host did not influence the respiration of kidney slices. Preputial-gland slices showed an extreme variation in QO₂ unrelated to treatment. The earliest, and smallest, cancer nodules permitting study had the characteristic neoplastic type of metabolism.