Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-02165-0012-0000-9
Chemical Name:	Ethylene thiourea (ETU)
CASRN:	96-45-7
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	669405
Study Result:	Positive

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Table Instructions and Notes:
Studies are indicated to be "Nontoxic" when the observed reductions in relative total growth did not indicate that the maximum tolerated dose was achieved.

Nonactivation Trial: 1 Experiment Call: Negative and Non-Toxic
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	86	102	78	30	37
			86	96	83	32
			83	100	79	32
			99	103	157	53
Test Chemical	Ethylene thiourea (ETU)	225	92	99	93	34	33
			102#	108	99	33	33
		450	95	96	101	36	28
			94	107	58	21	28
		900	73	85	72	33
		1800	63#	80	97	51	46
			71#	67	86	40	46
		3600	64#	74	85	44	36
			92#	89	76	28	36
Positive Control	Other Positive Control	15	36	21	196	181	154*
Positive Control			35	24	132	126	154*

Nonactivation Trial: 2 Experiment Call: Negative and Non-Toxic
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	80	116	54	23	26
			69	92	40	19
			69	93	65	31
			79#	99	69	29
Test Chemical	Ethylene thiourea (ETU)	225	83#	111	38	15	21
			90	104	71	26	21
		450	90	114	49	18	19
			82	109	48	20	19
		900	86	102	44	17	17
			102	96	55	18	17
		1800	90	98	36	13	15
			86	96	41	16	15
		3600	78	98	42	18	16
			84#	104	35	14	16
Positive Control	Methyl Methane Sulfonate	15	44	35	172	130	126*
Positive Control			43	37	157	122	126*

Induced S9 Trial: 1 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	77	101	46	20	17
			63	107	28	15
			71	111	27	13
			61	81	36	20
Test Chemical	Ethylene thiourea (ETU)	225	61	87	53	29	25
			63	97	39	21	25
		450	73	109	35	16	17
			65	104	37	19	17
		900	68	68	51	25	26
			82	92	66	27	26
		1800	91	118	98	36	35*
			73	97	73	33	35*
		3600	83	102	81	33	35*
			85	98	94	37	35*
Positive Control	3-Methylcholanthrene	2.5	51	32	195	128	130*
Positive Control			56	32	223	132	130*

Induced S9 Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	72	95	51	24	23
			82	106	47	19
			86	104	71	28
			69	96	45	22
Test Chemical	Ethylene thiourea (ETU)	1200	84	109	72	29	25
			72	95	48	22	25
		1800	84	89	88	35	37*
			87	87	103	40	37*
		2400	75	77	97	43	40*
			65	69	73	38	40*
		3000	73	92	104	47	46*
			78	71	103	44	46*
		3600	73	80	124	56	55*
			70	68	113	54	55*
Positive Control	3-Methylcholanthrene	2.5	47	25	418	300	269*
Positive Control			69	29	490	238	269*

Footnotes:
Asterisks(*) indicate significant responses.
r = rejected value due to quality control criteria
# = reduced sample size because of the loss of one culture dish due to contamination