Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-02669-0004-0000-9
Chemical Name:	Phenobarbital
CASRN:	50-06-6
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	952103
Study Result:	Positive

View Study Details | View Protocol | Download To Excel

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	Acetone	0	105	94	116	37	35
			95	102	92	32
			93	104	103	37
Test Chemical	Phenobarbital	31.3	79#	86	72	31
		62.5	59	65	57	32	32
			91	71	94	34
			80	75	73	31
		125	67#	70	52	26	36
			58#	59	81	46	36
		250	72	65	71	33	35
			94	72	122	43
			90	90	74	28
		500	85#	59	89	35	38
			76#	67	78	34
			79	71	109	46
		1000	70	58	91	44	39
			87	42	92	35	39
Positive Control	Ethyl Methane Sulfonate	250	74	36	910	409	409*

Nonactivation Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Acetone	0	70#	104	63	30	29
			62	97	54	29
			66#	95	66	34
			62	104	43	23
Test Chemical	Phenobarbital	250	49#	59	20	14	14
			48#	65	19	13
			51#	65	25	17
		500	56#	83	51	30	31
			54	73	51	32
			47	80	43	30
		750	61#	55	80	44	35
			61#	57	45	25
			59	42	65	37
		1000	61#	61	54	30	36
			69	59	73	35
			48	47	60	42
		1200	66#	40	85	43	61*
			53	28	136	86
			57	34	91	53
		1500	61	28	143	79	94*
			69#	57	101	49
			40#	19	186	155
		2000


Positive Control	Methyl Methane Sulfonate	10	49#	36	483	330	402*
			28	23	392	475	402*
	Methyl Methane Sulfonate	250	79	69	655	278	278*

Nonactivation Trial: 3 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Acetone	0	83	86	110	44	31
			91#	109	70	26
			87	100	58	22
			96	105	96	33
Test Chemical	Phenobarbital	600	81	77	112	46	43
			80	70	102	43
			69	65	84	40
		800	81	49	101	42	42
			69	55	90	43
			79	58	94	40
		1000	92	46	124	45	49*
			78	45	124	53
			80	49	117	49
		1250	80	49	130	54	54*
			86	49	127	49
			86	44	151	58
		1500	66	34	130	65	72*
			74	29	146	65
			65	25	164	85
		2000


Positive Control	Methyl Methane Sulfonate	5	74	77	345	156	189*
			61	51	407	222	189*
	Methyl Methane Sulfonate	10	36	16	375	349	361*
			50	32	561	373	361*

Induced S9 Trial: 1 Experiment Call: Negative
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Acetone	0	67	118	55	27	31
			71#	84	78	37
			87	101	62	24
			66	96	70	35
Test Chemical	Phenobarbital	200	67	69	75	37	32
			69	73	64	31
			63	81	51	27
		400	57#	81	58	34	30
			66	73	62	31
			67	85	48	24
		500	69	83	52	25	29
			78	89	66	28
			69#	73	68	33
		600	66	65	62	31	31
			56	63	48	28
			58	68	56	32
		800	64	41	106	55	42
			54	55	60	37
			72	57	70	32
Positive Control	3-Methylcholanthrene	2.5	97#	69	534	184	179*
			84	77	471	188
			96	61	473	165

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