ABSTRACT
The action of 5-androstene-3 beta,17 beta-diol (Adiol) on Thymidine Kinase (TK) was studied in the rat uterus. It appeared that Adiol, like 17 beta-estradiol (E2), could induce the synthesis of the fetal isoenzyme of TK. Its effects compared with those of E2, were delayed by 6 h and higher doses were required to reach the same levels of induction. The action of Adiol on TK was exclusively observed in tissues where E2 receptors were present. Moreover, Adiol could stimulate the activity of uterine DNA-polymerase alpha. These observations are additional evidence of the estrogen-like behaviour of Adiol. They suggest that it could participate in proliferative processes of tissues which are dependent on estrogens.
Subject(s)
Androstenediol/pharmacology , Androstenediols/pharmacology , Estradiol/pharmacology , Thymidine Kinase/biosynthesis , Uterus/enzymology , Androstenediol/metabolism , Animals , Cycloheximide/pharmacology , Cytosol/enzymology , DNA Polymerase II/metabolism , Dactinomycin/pharmacology , Enzyme Induction/drug effects , Female , Isoenzymes/biosynthesis , Kidney/enzymology , Liver/enzymology , Organ Size/drug effects , Rats , Rats, Inbred Strains , Receptors, Estradiol/metabolism , Uterus/anatomy & histologyABSTRACT
In human breast cancers, assays on thymidine kinase activity revealed the synthesis of large amounts of d-TTP. This fact suggested the presence of thymidylate kinase closely associated with thymidine kinase. Results obtained with experimental tumors were quite different. These tumors appeared inadequate for the study on thymidine metabolism in mammary cancers.
Subject(s)
Breast Neoplasms/enzymology , Isoenzymes/metabolism , Mammary Neoplasms, Experimental/enzymology , Nucleoside-Phosphate Kinase/metabolism , Phosphotransferases/metabolism , Thymidine Kinase/metabolism , Animals , Female , Humans , Kinetics , Rats , Rats, Inbred StrainsABSTRACT
In uteri from immature female rats, thymidine kinase activity was largely increased by administration of 5-androstene-3 beta, 17 beta-diol. Kinetic studies showed that the enzyme activity reached its maximum level 30 h after hormone administration. That increase in thymidine kinase activity was dose-dependent and could be related to the synthesis of new molecules of enzyme. Moreover, it was exclusively observed in target-organs for estrogens. It was concluded that 5-androstene-3 beta, 17 beta-diol which results from the metabolism of dehydroepiandrosterone had estrogen-like properties with regard to the induction of thymidine kinase.
