Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-02502-0008-0000-9
Chemical Name:	N,N'-Dicyclohexylthiourea
CASRN:	1212-29-9
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	028630
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: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	64	100	174	91	90
			69	103	218	106
			72#	97	162	75
Test Chemical	N,N'-Dicyclohexylthiourea	9.375	71	94	173	81	107
			45#	64	178.5	134	107
		18.75	52	22	190	121	116
			63#	21	210	111	116
		37.5	40	12	189	158	138
			47#	18	165	117	138
		75	37	7	337	306	259*
			42	6	268	211	259*
		150

Positive Control	Ethyl Methane Sulfonate	250	58	63	506	293	350*
Positive Control			39	48	481	408	350*

Nonactivation Trial: 3 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	91	105	131	48	53
			72	99	125	58
			91	97	132	49
			101	99	172	57
Test Chemical	N,N'-Dicyclohexylthiourea	18.75	86	62	90	35	48
			79	62	143	60	48
		37.5	95	25	236	83	87*
			80	22	216	91	87*
		75	87	27	157	61	68
			75	25	169	75	68
		150	57	6	497	290	268*
			60	10	443	246	268*
Positive Control	Ethyl Methane Sulfonate	250	70	73	632	302	376*
Positive Control			49	44	660	449	376*

Non-Induced S9 Trial: 1 Experiment Call: Rejected
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	84	106	174	69	71
			94	92	197	70
			76	112	146	64
			76	89	183	81
Test Chemical	N,N'-Dicyclohexylthiourea	18.75	84	84	212	84	80
			101	87	228	75	80
		37.5	76	46	184	80	75
			89	44	185	69	75
		75	85	35	225	88	80
			93	45	201	72	80
		150	73	29	219	100	85
			97	32	204	70	85
		300	78	25	205	88	89
			70	33	189	90	89
Positive Control	3-Methylcholanthrene	2.5	82	79	273	111	117*
Positive Control			99	81	367	124	117*

Induced S9 Trial: 1 Experiment Call: Negative
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	78	95	96	41	50
			80	111	130	54
			81#	93	130.5	54
Test Chemical	N,N'-Dicyclohexylthiourea	9.375	106	105	141	44
		18.75	91	84	116	42	44
			85	72	115	45	44
		37.5	118#	44	138	39
		75	86#	24	84	33	35
			88#	26	99	37	35
		150	82	11	111	45	37
			117#	14	102	29	37
Positive Control	3-Methylcholanthrene	2.5	44#	24	388.5	293	310*
Positive Control			39	18	385	326	310*

Induced S9 Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Methanol	0	84	97	175	70	73
			84	119	139	55
			74	95	181	81
			59	88	152	85
Test Chemical	N,N'-Dicyclohexylthiourea	18.75	63	74	156	82	88
			59	73	165	93	88
		37.5	84	43	204	81	102
			63	32	230	122	102
		75	62	26	293	157	153*
			49	21	220	150	153*
		150	68	20	322	159	158*
			58	21	271	157	158*
		300	71	25	321	151	152*
			64	20	293	153	152*
Positive Control	3-Methylcholanthrene	2.5	29	13	707	813	866*
Positive Control			27	9	754	920	866*

Induced S9 Trial: 3 Experiment Call: Inconclusive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	29r	28	213	246	81
			33r	44	169	172
			76	113	182	80
			77	87	190	82
Test Chemical	N,N'-Dicyclohexylthiourea	18.75	66	57	184	93	84
			87	54	196	75	84
		37.5	74	45	167	75	82
			85	35	228	89	82
		75	75	23	216	97	106
			58	26	201	116	106
		150	61	32	158	87	85
			83	35	209	84	85
		300	88	22	191	73	80
			59	30	153	87	80
Positive Control	3-Methylcholanthrene	2.5	42	29	624	501	535*
Positive Control			34	22	584	570	535*

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