In vivo mutagenicity assessment of orally treated tert-butyl hydroperoxide in the liver and glandular stomach of MutaMouse

Table 1 Mutant frequencies in the livers of MutaMouse given TBHP. Male mice were dosed once daily for 28 days (oral administration, tissues were collected 3 days after final administration)

Substance	Dose (mg/kg/day, p.o.)	Animal ID No	Number of plaque	Number of packaging	Number of mutants	Mutant frequency (× 10⁻⁶)	Group Mean ± S.D. (× 10⁻⁶)
0.5% MC	0	3001	666,900	1	32	48.0	47.2 ± 10.6
		3002	725,400	1	22	30.3
		3003	635,400	1	35	55.1
		3004	965,700	1	44	45.6
		3005	1,071,900	1	61	56.9
TBHP	75	3101	945,900	1	33	34.9	45.8 ± 13.1
		3102	800,100	1	30	37.5
		3103	395,100	1	26	65.8
		3104	1,126,800	1	59	52.4
		3105	990,000	1	38	38.4
	150	3201	676,800	1	26	38.4	42.5 ± 10.5
		3202	904,500	1	45	49.8
		3203	1,066,500	1	60	56.3
		3204	642,600	1	19	29.6
		3205	1,348,200	1	52	38.6
	300	3301	736,200	1	29	39.4	42.7 ± 8.2
		3302	981,900	1	54	55.0
		3303	1,429,200	1	50	35.0
		3304	771,300	1	36	46.7
		3305	1,126,800	1	42	37.3
ENU	100	3401	559,800	1	107	191.1	183.5 ± 14.3 *
		3402	920,700	1	176	191.2
		3403	1,164,600	1	215	184.6
		3404	649,800	1	103	158.5
		3405	582,300	1	112	192.3

0.5% MC: Control group (0.5 w/v% methylcellulose solution, 10 ml/kg)
ENU: Positive control (N-ethyl-N-nitrosourea, 10 ml/kg, i.p., once daily for 2 days, expression period; 10 days)
^*Statistically significant difference from the negative control (Student’s t-test: p < 0.05)

ISSN: 1880-7062