VERGLEICHENDE UNTERSUCHUNGEN ÜBER DIE AUFNAHME UND DEN STOFFWECHSEL VON [4-14C]17β-ÖSTRADIOL BEIM SPONTANEN MAMMACARCINOM DER MAUS UND IN VERSCHIEDENEN GEWEBEN DER RATTE

Abstract

ABSTRACT [4-14C] 17β-Oestradiol was incubated with slices of spontaneous mammary carcinoma (Ca.) of the mouse as well as with slices of spontaneous fibroadenoma (Ad.), hyperplastic mammary tissue (Ma.), fat tissue (Fa.), skeletal muscle (Mu.) and liver (Li.) of the rat. After incubation, the tissue slices and the media were worked up separately. In all experiments, [4-14C] oestrone and a radioactive »polar« fraction were detected as metabolites of [4-14C]17β-oestradiol. Ca. of the mouse differ from Ad. and Ma. of the rat by a higher conversion rate of [4-14C] 17β-oestradiol to its metabolites and a higher rate of formation of the radioactive »polar« fraction. The formation of [4-14C] oestrone varied considerably in Ca. of the mouse and was similar to that found in Ad. and Ma. of the rat. As was to be expected, the rate of conversion of [4-14C] 17β-oestradiol to its metabolites was much higher in Li. than in normal and in neoplastic mammary tissue; however, the conversion rates in Fa. and Mu. were similar to those in the various mammary tissues. With exception of Li., the formation of [4-14C] oestrone was about the same in all tissues investigated. The total amount of the »polar« fraction (sum of radioactivity in the tissue and in the incubation medium) was significantly higher in the Ca. of the mouse and the Li. of the rat than in all other tissues investigated. The uptake ratios (amount of steroid in tissue/g × ml incubation medium/amount of steroid in the medium) for [4-14C] 17β-oestradiol and its metabolites were more than 1 in all tissues studied. The average of the uptake ratios for [4-14C] 17β-oestradiol, [4-14C] oestrone and the radioactive »polar« fraction showed the same order of magnitude for the Ca. of the mouse and for the Mu. and Li. of the rat. However, this value was always lower than that for Ma. and Fa. of the rat and always higher than that for the Ad. of the rat.