Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-02756-0028-0000-2
Chemical Name:	Pyridine
CASRN:	110-86-1
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	746434
Study Result:	Negative

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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	Fischer Medium	0	112	102	95	28	30
			101	89	92	31
			108	103	100	31
			99	106	86	29
Test Chemical	Pyridine	312.5	124r	115	112	30
			123r	115	98	27
		625	105	102	95	30	34
			89	100	99	37	34
		1250	86	101	80	31	26
			73	88	47	21	26
		2500	78	71	56	24	26
			94	69	81	29	26
		5000	88	77	113	43	34
			82	70	60	24	34
Positive Control	Methyl Methane Sulfonate	15	49	26	195	133	160*
Positive Control			43	26	239	186	160*

Nonactivation Trial: 2 Experiment Call: Equivocal
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Fischer Medium	0	65	102	120	62	49
			84	97	122	49
			99	102	136	46
			76	98	89	39
Test Chemical	Pyridine	1000	58	90	106	61	63
			82	101	160	65	63
		2000	68	78	167	81	75
			74	77	154	69	75
		3000	71	76	161	76	77*
			78	68	182	78	77*
		4000	55	76	154	94	81*
			47	68	97	68	81*
		5000	69	66	151	73	85*
			48	57	138	97	85*
Positive Control	Methyl Methane Sulfonate	15	24	20	473	671	610*
Positive Control			27	23	440	550	610*

Nonactivation Trial: 3 Experiment Call:
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Fischer Medium	0	102	106	85	28	25
			71	84	70	33
			108	110	67	21
			98	100	60	20
Test Chemical	Pyridine	2000	79	85	53	22	24
			90	87	68	25	24
		3000	90	79	64	24	25
			116	85	89	26	25
		4000	88	79	145	55	47*
			72	75	86	40	47*
		5000	89	67	79	30	30
			82	70	73	30	30
Positive Control	Methyl Methane Sulfonate	15	23	13	103	151	159*
Positive Control			25	14	126	166	159*

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	Fischer Medium	0	74	105	141	64	55
			83	102	137	55
			79	104	124	53
			90	90	126	47
Test Chemical	Pyridine	1000	89	96	152	57	56
			82	88	133	54	56
		2000	77	99	123	53	68
			94	77	230	82	68
		3000	89	80	140	52	71
			77	86	204	89	71
		4000	78	79	147	63	59
			100	70	167	55	59
		5000	98	73	207	70	63
			95	81	158	55	63
Positive Control	3-Methylcholanthrene	2.5	43	20	726	561	556*
Positive Control			50	18	820	552	556*

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	Fischer Medium	0	105	98	159	50	52
			100	93	188	62
			91	108	138	50
			85	101	111	43
Test Chemical	Pyridine	2000	87	108	119	46	41
			86	104	95	37	41
		3000	79	105	117	49	43
			78	101	87	37	43
		4000	84	91	107	42	41
			80	97	94	39	41
		5000	109	84	115	35	33
			109	78	101	31	33
Positive Control	3-Methylcholanthrene	2.5	58	28	791	451	436*
Positive Control			54	24	686	421	436*

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