Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-02667-0008-0000-1
Chemical Name:	Phenformin hydrochloride
CASRN:	834-28-6
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	075668
Study Result:	Equivocal

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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: Equivocal
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	78	106	126	54	65
			68	108	144	71
			87	102	160	61
			76	85	168	73
Test Chemical	Phenformin hydrochloride	100	84	83	177	70	73
			83#	71	190.5	77	73
		200	72	72	191	89	81
			82	63	183	74	81
		400	61	60	163	89	86
			64	59	159	82	86
		800	68	37	226	111	97
			87	38	216	83	97
		1600	73	7	213	98	111*
			51	6	188	124	111*
Positive Control	Methyl Methane Sulfonate	15	31	20	509	541	468*
Positive Control			42	21	494	394	468*

Nonactivation Trial: 2 Experiment Call: Equivocal
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	102	89	95	31	30
			92	99	87	31
			86	105	80	31
			99	106	82	28
Test Chemical	Phenformin hydrochloride	800	76	32	127	55	46
			73	36	78	36	46
		900	73	20	114	52	45
			58	20	66	38	45
		1000	78#	11	92	39	43
			72	10	102	47	43
		1100	64	6	93	49	47
			69	5	95	46	47
		1200	60	4	145	80	62*
			66	5	86	44	62*
		1300

Positive Control	Methyl Methane Sulfonate	15	30#	24	166.5	186	170*
Positive Control			37	21	170	155	170*

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	76	98	151	67	61
			90	92	127	47
			80	106	150	63
			68	105	135	67
Test Chemical	Phenformin hydrochloride	600	73	36	108	49	53
			64	37	111	58	53
		800	53	28	82	51	60
			57	30	118	69	60
		1000	61	17	121	66	73
			74	19	178	81	73
		1200

Positive Control	3-Methylcholanthrene	2.5	37	11	527	473	472*
Positive Control			37	14	527	471	472*

Induced S9 Trial: 2 Experiment Call: Negative
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	79	95	70	29	30
			79	98	71	30
			74	91	68	31
			75	116	68	30
Test Chemical	Phenformin hydrochloride	300	66	48	88	44	31
			62	39	34	18	31
		500	62	25	54	29	28
			58	20	48	28	28
		700	48	16	75	52	45
			56	12	63	37	45
		900	45	7	46	34	27
			33	7	19	19	27
		1100
		1300

Positive Control	3-Methylcholanthrene	2.5	43	30	425	332	334*
Positive Control			51	33	513	336	334*

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	76	112	98	43	44
			77	88	113	49
			80	101	106	44
			59	99	68	39
Test Chemical	Phenformin hydrochloride	607	70	89	64	30	34
			81	103	91	37	34
		780	73	73	70	32	31
			98	37	90	31	31
		953	95	65	51	18	18
			101	63	52	17	18
		1127	84	57	39	16	21
			84	52	66	26	21
		1300	100	35	103	34	29
			78	38	54	23	29
Positive Control	3-Methylcholanthrene	2.5	46	39	571	414	392*
Positive Control			51	39	567	369	392*

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