Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-02660-0002-0000-8
Chemical Name:	Phenacetin
CASRN:	62-44-2
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	838305
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: Inconclusive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	79	84	83	35	23
			83#	109	40.5	16
			86	97	58	23
			83	109	46	19
Test Chemical	Phenacetin	62.5	75	71	53	24	21
			78#	74	30	13
			86#	87	66	26
		125	98	75	55	19	24
			78	66	69	30	24
		250	82	62	61	25	20
			91	77	46	17
			117	97	69	20
		500	79	57	60	25	25
			83	75	65	26
			82	66	56	23
		750	85	83	64	25	25
			114	66	69	20
			87	68	79	30
		1000	77	34	41	18	18
			113	63	60	18	18
Positive Control	Ethyl Methane Sulfonate	250	54#	32	1054.5	651	543*
			62	46	964	520
			75	51	1035	458

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	112	113	94	28	23
			95	99	56	20
			95	102	64	22
			82	85	54	22
Test Chemical	Phenacetin	125	90	85	47	18	19
			88#	78	55.5	21
			89	88	50	19
		250	99	74	82	28	24
			82	68	57	23
			97	58	65	22
		500	82	60	70	29	26
			91	72	80	29
			88	80	53	20
		1000	82	23	73	30	34
			101	51	104	34
			82	49	95	39
		1500

			49	5	148	102
		2000


Positive Control	Ethyl Methane Sulfonate	250	46	25	689	499	626*
			43	28	637	498
			24	13	622	882

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	96	94	80	28	25
			97	101	89	31
			105#	92	69	22
			101	112	62	21
Test Chemical	Phenacetin	125	102	94	70	23	23
			93	58	68	24
			71	65	49	23
		250	96	71	67	23	25
			94	58	69	25
			95	72	75	26
		500	110	100	81	25	23
			96	68	60	21
			106	86	78	25
		1000	99	54	102	34	35
			111	72	113	34
			90	62	96	36
		1500	103#	64	85.5	28	49*
			95	19	219	77
			86	31	112	43
		2000	103	32	154	50	65*
			79	9	163	69
			82	10	186	76
Positive Control	Ethyl Methane Sulfonate	250	86	48	824	319	344*
			92	62	805	293
			69	52	869	421

Non-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	58	101	72	41	35
			62	97	63	34
			73	101	62	28
Test Chemical	Phenacetin	250	54#	52	63	39	38
			49	71	56	38
			59	87	65	37
		500	56#	81	64	38	38
			57	69	72	42
			68	60	67	33
		750	66	59	108	54	52
			48	86	86	60
			48	72	61	42
		1000	88#	102	113	43	42
			80	108	97	41	42
		1500	69#	45	105	51	60*
			80	29	177	74
			66	69	111	56
		2000	89#	15	233	87	88*
			64	15	138	72
			74	9	228	103
Positive Control	3-Methylcholanthrene	3.5	62	64	304	164	186*
Positive Control			58	57	364	209	186*

Induced S9 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	76	104	54	24	33
			83	122	46	19
			82	93	115	47
			71	81	90	42
Test Chemical	Phenacetin	62.5	68#	80	75	37	37
			63	71	88	47
			93	119	80	29
		125	80	88	75	31	38
			70	93	73	35
			60	69	87	48
		250	80	82	113	47	43
			72#	88	96	44
			64#	83	72	38
		500	88	82	137	52
		750	76#	68	129	57	49*
			80	105	98	41
			73#	80	109.5	50
		1000	98	72	161	55	67*
			30	28	107	118
			58#	73	51	29
Positive Control	3-Methylcholanthrene	2.5	35#	17	544.5	516	367*
			57	39	492	290
			49	35	438	296

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	92	86	71	26	18
			107	97	42	13
			108	116	48	15
			122r	102	67	18
Test Chemical	Phenacetin	125	103	89	57	18	20
			110	95	53	16
			101	61	74	24
		250	117	75	73	21	23
			103	73	78	25
			101	100	72	24
		500	95#	80	82.5	29	27
			78	56	55	24
			87	76	74	29
		1000	98	75	90	31	27
			114	71	78	23
			111	76	87	26
		1500	110	22	88	27	30*
			98	51	77	26
			84	41	91	36
		2000	78	33	70	30	27
			91	35	90	33
			105	28	60	19
Positive Control	3-Methylcholanthrene	2.5	86	49	450	174	155*
			86	61	392	152
			85	53	352	139

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