Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-02971-0009-0000-0
Chemical Name:	Trimethylthiourea
CASRN:	2489-77-2
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	360906
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: Inconclusive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	70	93	68	32	30
			74	109	70	32
			74	93	46	21
			71	106	74	35
Test Chemical	Trimethylthiourea	75	91	105	92	34	35
			94	109	102	36	35
		100	85	119	74	29	34
			25	31	28	38	34
		125	103	117	94	31	27
			97	123	68	23	27
		150	95	130	75	26	34
			95	117	117	41	34
Positive Control	Methyl Methane Sulfonate	15	33	34	203	206	201*
Positive Control			30	35	177	196	201*

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	82#	86	124.5	51	52
			88	117	132	50
			95#	106	148.5	52
			84#	91	138	55
Test Chemical	Trimethylthiourea	1800	96	74	168	59	56
			83#	66	132	53	56
		2600	93	60	179	64	59
			107	72	172	54	59
		3400	85	48	128	50
		4200	101	21	307	102	107*
			105	20	353	112	107*
		5000	80	13	493	205	203*
			86	15	516	201	203*
Positive Control	Methyl Methane Sulfonate	15	53	33	467	295	290*
Positive Control			51	30	437	285	290*

Nonactivation Trial: 3 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	94	105	130	46	45
			110	102	148	45
			113	95	155	46
			92	98	125	45
Test Chemical	Trimethylthiourea	1800	88	48	173	65	69
			83	47	182	73	69
		2600	102	46	186	61	70
			83	38	196	78	70
		3400	88	36	117	44	53
			95	26	177	62	53
		4200	103	20	457	149	142*
			87	18	353	135	142*
		5000	82	12	1057	431	422*
			101	11	1246	413	422*
Positive Control	Methyl Methane Sulfonate	15	38	24	285	251	234*
Positive Control			40	28	258	218	234*

Induced S9 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	67	110	90	45	56
			71	94	108	51
			68	94	159	78
			73	101	112	51
Test Chemical	Trimethylthiourea	200	95	96	136	48	53
			82	97	146	59	53
		400	86	97	121	47	48
			78	84	112	48	48
		600	83	100	88	35	43
			78	87	118	51	43
		800	69	81	120	58	45
			79	102	74	31	45
		1000	92	88	127	46	48
			72	76	105	49	48
Positive Control	3-Methylcholanthrene	2.5	47	30	374	266	285*
Positive Control			47	36	424	303	285*

Induced S9 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	90	100	65	24	29
			96	94	67	23
			93	106	84	30
			87	100	104	40
Test Chemical	Trimethylthiourea	200	79	78	63	27	29
			73	91	70	32	29
		400	77	79	75	33	33
			71	69	71	33	33
		600	80	67	126	53	45
			84	71	93	37	45
		800	77	74	71	31	35
			82	65	96	39	35
		1000	94	69	88	31	33
			74	67	75	34	33
Positive Control	3-Methylcholanthrene	2.5	55	27	397	241	253*
Positive Control			51	26	401	264	253*

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