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

Table 2 Mutant frequencies in the glandular stomach 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	1,215,900	1	54	44.4	44.2 ± 9.0
		3002	575,100	1	32	55.6
		3003	890,100	1	28	31.5
		3004	908,100	1	37	40.7
		3005	739,800	1	36	48.7
TBHP	75	3101	1,323,900	1	46	34.7	41.0 ± 11.6
		3102	891,900	1	26	29.2
		3103	669,600	1	23	34.3
		3104	888,300	1	46	51.8
		3105	1,015,200	1	56	55.2
	150	3201	497,700	1	16	32.1	42.5 ± 11.1
		3202	1,053,000	1	49	46.5
		3203	886,500	1	30	33.8
		3204	724,500	1	43	59.4
		3205	887,400	1	36	40.6
	300	3301	828,000	1	40	48.3	46.3 ± 7.0
		3302	1,122,300	1	50	44.6
		3303	1,343,700	1	58	43.2
		3304	1,100,700	1	42	38.2
		3305	1,086,300	1	62	57.1
ENU	100	3401	957,600	1	375	391.6	410.9 ± 20.5 *
		3402	1,125,000	1	490	435.6
		3403	1,607,400	1	647	402.5
		3404	1,238,400	1	489	394.9
		3405	916,200	1	394	430.0

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)
^*Significant difference from the negative control (Student's test: p < 0.05)

ISSN: 1880-7062