Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-02915-0008-0000-7
Chemical Name:	Tolbutamide
CASRN:	64-77-7
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	465250
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	97	99	93	32	30
			88	100	71	27
			98	97	91	31
			95	104	87	31
Test Chemical	Tolbutamide	100	57	76	73	43	44
			59	74	81	46	44
		200	80	73	101	42	42
			63	70	79	42	42
		400	53	57	89	56	46
			68	63	73	36	46
		800	60	53	90	50	44
			56	48	63	37	44
		1600	75	41	57	25	27
			74	38	64	29	27
Positive Control	Methyl Methane Sulfonate	15	43	29	184	144	180*
Positive Control			29	18	191	216	180*

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	72	82	92	43	34
			84	110	92	37
			75	94	60	27
			73	115	67	31
Test Chemical	Tolbutamide	1000	76	93	94	41	40
			71	90	82	38	40
		1200	62	66	90	49	49
			60	82	88	49	49
		1400	69	71	77	37	35
			75	73	74	33	35
		1600	76	62	80	35	34
			83	74	84	34	34
		1800	79	70	75	32	32
			73	66	70	32	32
Positive Control	Methyl Methane Sulfonate	15	32	28	225	238	182*
Positive Control			42	33	159	125	182*

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	60	110	158	87	66
			64	107	115	60
			56	83	84	50
			39r	62	79	68
Test Chemical	Tolbutamide	200	92	119	131	48	52
			43	99	71	56	52
		400	59	85	97	55	51
			65	114	93	48	51
		800	48	60	60	42	52
			55	90	103	62	52
		1000	60	74	90	50	48
			68	100	94	46	48
		1400	48	66	85	59	64
			72	133	151	70	64
		1800

Positive Control	3-Methylcholanthrene	2.5	40	25	488	407	454*
Positive Control			33	24	502	502	454*

Induced S9 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	72#	100	85	39	48
			59	102	92	52
			71	95	102	48
			68	104	111	55
Test Chemical	Tolbutamide	700	41	45	101	81	77*
			51#	55	113	73	77*
		900	57	37	219	128	125*
			55	36	201	123	125*
		1100	63	23	277	146	159*
			47	16	242	172	159*
		1300
		1500

Positive Control	3-Methylcholanthrene	2.5	27	11	437	533	482*
Positive Control			39	14	498	431	482*

Induced S9 Trial: 3 Experiment Call: Negative
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	89	112	153	57	59
			74	107	105	47
			79	86	170	72
			89	95	159	60
Test Chemical	Tolbutamide	700	93#	86	126	45	61
			80	77	185	77	61
		900	76	70	179	79	71
			75	85	142	63	71
		1100	102	64	154	50	60
			98	68	201	69	60
		1300	95	60	168	59	61
			103	79	194	63	61
		1500	85	32	125	49	63
			65	20	152	78	63
		1700

Positive Control	3-Methylcholanthrene	2.5	48	24	337	235	244*
Positive Control			57	19	431	253	244*

Induced S9 Trial: 4 Experiment Call: Negative
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	66	112	70	36	41
			74	108	93	42
			57	84	94	55
			60#	95	55	31
Test Chemical	Tolbutamide	1100	73	59	88	40	47
			70	58	114	54	47
		1200	63	55	96	51	43
			95	90	100	35	43
		1300	75	74	81	36	29
			89	59	61	23	29
		1400	77	58	84	36	35
			78	56	81	35	35
		1500	69	26	73	35	41
			89	32	123	46	41
		1600

Positive Control	3-Methylcholanthrene	2.5	41	21	421	342	283*
Positive Control			41	27	273	225	283*

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