[The role of UDP glucuronosyl- and sulfotransferases in the butylhydroxytoluene suppression of the mutagenic action of carcinogenic nitroso compounds and cyclophosphane].

Treatment with butylated hydroxytoluene (BHT) was shown to stimulate the activity of UDP-glucuronosyltransferase and to inhibit that of sulfotransferase in liver of Wistar male rats. Addition of UDP-glucuronic acid to incubation medium in Ames' test using BHT-pretreated subfractions of rat liver resulted in decreased mutagenicity of nitrosodiethylamine, nitrosomorpholine and cyclophosphamide. Further treatment with 3'-phosphoadenosine-5'-phosphosulfate failed to affect mutagenic activity of the promutagens tested.

[Ames test study of the effect of 2nd-phase biotransformation reactions on the level of mutagenic action of a number of chemical compounds].

Introduction of cosubstrates for reactions of conjugation with the reduced glutathione, glucuronic acid and sulphate is shown to modify (increase or decrease) the level of mutagenic effect of thiophosphamide, nitrosomethylurea and DDDTDP on S. typhimurium TA 1950 or TA 1534.

[Study of the biotransformation of various antineoplastic agents using the Ames test].

The Ames test on indicator bacteria S. typhimurium TA 1950 and TA 100 and the differential spectrophotometry have shown that cytochrome P-450-dependent monooxygenases of mammalian liver participate in the metabolism of antitumour drugs (cyclophosphamide, thiophosphamide) and of nitrosomorpholine (promutagen). Data concerning prospidin indicate that microsomal liver enzymes either induce no metabolic transformations of this preparation or the formed metabolites possess the mutagenic activity similar to that of the parent compound.

[The nature of DNA damage and its repair after treatment of bacteria with dioxidine].

The nature of the lethal effect of antimicrobial drug dioxidin was studied. The treatment of bacterial cells by dioxidin results in an instant repression of DNA synthesis and formation of single strand gaps in DNA molecule. The repair of single strand gaps in polA+ cells involves the DNA polymerase I.

[Modifying action of drug preparations on the effect of promutagen compounds].

The Ames test has shown that the action of nitrosomorpholine and cyclophosphane promutagens on bacteria of Salmonella typhimurium TA 1950 increases while using S-9 liver fraction of rats treated with pharmaceuticals of amidopyrine, reserpine and pyrazidol and decreases while using those treated with phenazepam.