Reference

Tests for the induction of mutations to ouabain or 6-thioguanine resistance in mouse lymphoma L5178Y cells

Tests for the induction of mutations to ouabain or 6-thioguanine resistance in mouse lymphoma L5178Y cells. Garner, R. Colin; Campbell, Jean (Cancer Res. Unit, Univ. York, York, UK). Prog. Mutat. Res., 5(Eval. Short-Term Tests Carcinog.), 525-9 (English) 1985. CODEN: PMRSDJ. ISSN: 0731-2849. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) Section cross-reference(s): 1, 2 None of 10 test chems. were potent mammalian cell mutagens to mouse lymphoma L5178Y cells using a fluctuation assay protocol when compared with potent carcinogens such as benzo[a]pyrene. Safrole (I) [94-59-7], o-toluidine [95-53-4], diethylstilbestrol [56-53-1], benzene [71-43-2] and acrylonitrile [107-13-1] induced mutations to either ouabain [630-60-4] or 6-thioguanine [154-42-7] resistance. Of these only o-toluidine required liver S9 mix for mutation induction; acrylonitrile appeared to be the most active of the 10 chems. tested. The 2 noncarcinogens, benzoin [119-53-9] and caprolactam [105-60-2], failed to induce mutations. The results obtained reflect the marginal genotoxicity of the test chems. in this in vitro assay and raise the question of whether or not some of the test chems. are genuine tumor initiators.

A study of the frequency of sister-chromatid exchange and of thioguanine-resistant cells in mouse spleen lymphocytes after in vivo exposure to ethylnitrosourea

A study of the frequency of sister-chromatid exchange and of thioguanine-resistant cells in mouse spleen lymphocytes after in vivo exposure to ethylnitrosourea. Jones, I. M.; Burkhart-Schultz, K.; Carrano, A. V. (Lawrence Livermore Natl. Lab., Univ. California, Livermore, CA 94550, USA). Mutat. Res., 143(4), 245-9 (English) 1985. CODEN: MUREAV. ISSN: 0027-5107. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) The frequency of sister chromatid exchange (SCE) and the frequency of thioguanine [154-42-7]-resistant (TGr) cells among the lymphocytes of mouse spleen following acute, i.p. exposure to ENU [759-73-9] were measured. The responses of these 2 endpoints were monitored both as a function of the dose of ENU injected, ranging from 0 to 70 mg/kg, and as a function of time after injection, from 1 day to 72 days. The SCE frequency response was highest 1 day after the ENU was injected, increasing 2.5-fold over control values for mice that received 70 mg/kg, and declined to control values in all animals by 72 days. SCE showed a linear dose response both at 1 day and 8 days after injection. The frequency of TGr cells was at control levels at 1 day, but at 15, 36 and 72 days after ENU injection the frequency of TGr cells showed a linear dose response. In addn., the frequency of TGr cells increased linearly with time for both the 35 and 70 mg/kg doses. The frequency of TGr cells for mice that had received 70 mg ENU/kg 72 days previously, was 100-fold higher than in control animals, giving a frequency of 1.4 ′ 10-4.