2-ethylhexylamine

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in mammalian cells

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

Version / remarks:

as of 1997

Principles of method if other than guideline:

HPRT assay for the detection of mutations at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus (6-thioguanine [6TG] resistance) in mouse lymphoma cells using a fluctuation protocol according to Cole et al. 1983.

Reference:
Cole J, Arlett C F, Green M H L, Lowe J and Muriel W 1983: A comparison of the agar cloning and microtitration techniques for assaying cell survival and mutation frequency in L5178Y mouse lymphoma cells. Mutation Research, 111, 317-386

GLP compliance:

yes (incl. QA statement)

Type of assay:

other: mammalian cell gene mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Octylamine

EC Number:

203-916-0

EC Name:

Octylamine

Cas Number:

111-86-4

Molecular formula:

C8H19N

IUPAC Name:

octan-1-amine

Method

Target gene:

Induction of a forward mutation in the X-linked hprt locus: Resistance to the toxic analogue 6-thioguanine (6TG) results from lack of hypoxanthine-guanine phosphoribosyl transferase (HPRT) activity. Thus, the hprt-negative mutants are unable to use 6TG and survive in its presence.

Species / strain

Species / strain / cell type:

mouse lymphoma L5178Y cells

Details on mammalian cell type (if applicable):

- Type and identity of media: RPMI media (containing antibiotics and varying concentrations of horse serum, heat-inactivated, from 0 - 20 %)
- Properly maintained: yes
- Periodically checked for Mycoplasma contamination: yes
- Periodically "cleansed" against high spontaneous background: yes,
- Other procedures: purge of TK-negative mutants

Additional strain / cell type characteristics:

other: TK proficient (TK+)

Metabolic activation:

with and without

Metabolic activation system:

post-mitochondrial fraction from livers of male SD rats previously induced with Arochlor-1254

Test concentrations with justification for top dose:

Experiment 1: 0, 10, 20, 30, 40, 50, 60, 70, 75, 80, 90, 100 µg/mL (evaluated)
Experiment 2: 0, 10, 20, 30, 40, 50, 55, 60, 65, 70, 72.5, 75, 80, 90 µg/mL (evaluated)

Vehicle / solvent:

- Vehicle/solvent used: DMSO
- Justification for choice of solvent/vehicle: sufficient water solubility of the test substance

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

DMSO, diluted 100-fold in treatment medium

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitroquinoline-N-oxide (-S9); benzo(a)pyrene (+S9)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium, incubation in centrifuge tubes, culture flasks, and wells of microtiter plates, depending on the operation step

DURATION
- Preincubation period: no data, pre-culture in RPMI 10 after thawing up to an appropriate cell density
- Exposure duration: 3 h
- Incubation temperature: 37 +- 1 °C
- Expression time (cells in growth medium): 7 d
- Selection time: 12 to 13 d

SELECTION AGENT: 6-thioguanine (6-TG)

NUMBER OF REPLICATIONS: 2

NUMBER OF CELLS EVALUATED: Selection of 6-TG resistance: 4 microtiter plates of 96 wells each; at 2 x10^4 cells per well each
(= 384 x 2 x10^4 cells per test concentration)

DETERMINATION OF CYTOTOXICITY
- Method: Relative survival in the presence and absence of test substance (by visual counting of viable clones in microtiter plates)

DETERMINATION of VIABILITY (after expression period)
- Method: visual counting of viable clones in microtiter plates

DETERMINATION of 6-TG RESISTANCE (after expression period)
- Method: visual inspection of microtiter plates for the number wells containing clones.

Evaluation criteria:

ACCEPTANCE CRITERIA
The assay was considered valid if the following criteria were met:
1. the mutant frequencies in the negative (vehicle) control cultures fell within the normal range (not more than three times the historical mean value)
2. at least one concentration of each of the positive control chemicals induced a clear increase in mutant frequency (the difference between the positive and negative control mutant frequencies was greater than half the historical mean value).

EV ALUATION CRITERIA
For valid data, the test article was considered to induce forward mutation at the hprt locus in mouse lymphoma L5178Y cells if:
1. the mutant frequency at one or more concentrations was significantly greater than that of the negative control (p < 0.05)
2. there was a significant concentration﷓relationship as indicated by the linear trend analysis (p < 0.05)
3. the effects described above were reproducible.
Results that only partially satisfied the assessment criteria described above were considered on a case-by-case basis.

Statistics:

Statistical significance of mutant frequencies was carried out according to the UKEMS guidelines. Thus the control log mutant frequency (LMF) was compared with the LMF from each treatment concentration, and secondly the data were checked for a linear trend in mutant frequency with test article treatment. These tests require the calculation of the heterogeneity factor to obtain a modified estimate of variance.

Reference:
Robinson et al. 1990: Statistical evaluation of bacterial/mammalian fluctuation tests. In Statistical Evaluation of Mutagenicity Test Data (Ed D J Kirkland), Cambridge University Press, pp 102 – 140.

Results and discussion

Test results

Key result

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

dose-related: The highest concentration to reliably provide >10 % RS was 40.41 µg/mL in the absence and 80.81 µg/mL in the presence of S9.

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: marked increases of >= 1 pH unit at >= 1293 µg/mL
- Effects of osmolality: no
- Evaporation from medium: no
- Precipitation: no

RANGE-FINDING/SCREENING STUDIES: for cytotoxicity testing up to 1293 µg/mL

COMPARISON WITH HISTORICAL CONTROL DATA: Acceptance criterion, Control/Historical ratio > 0.5, fulfilled for positive controls
(See Appendices)

Any other information on results incl. tables

Summary of mutation data [table 8; means of two replicate cultures]

 

Experiment 1 (3 hour treatment in the absence and presence of S-9)

[for individual replicates, see Appendix 2, Table 10 (-S9), and Appendix 3, Table 18 (+S9)]

 

Treatment (µg/mL)	-S-9			Treatment (µg/mL)	+S-9
	% RS	MF§			% RS	MF§
0	100	5.84		0	100	3.74
20	86	6.48	NS	20	92	3.07	NS
30	68	5.98	NS	30	89	2.46	NS
40	46	7.90	NS	40	73	3.42	NS
50	43	7.15	NS	50	55	3.37	NS
60	18	5.93	NS	60	43	5.09	NS
				70	24	2.22	NS
				75	12	2.11	NS
Linear trend			NS	Linear trend			NS
NQO				B[a]P
0.1	63	19.94		2	63	48.97
0.15	52	30.99		3	19	163.83

 

Experiment 2 (3 hour treatment in the absence and presence of S-9)

[for individual replicates, see Appendix 4, Table 26 (-S9), and Appendix 5, Table 34 (+S9)]

 

Treatment (µg/mL)	-S-9			Treatment (µg/mL)	+S-9
	% RS	MF§			% RS	MF§
0	100	4.98		0	100	4.40
10	86	4.14	NS	20	93	4.88	NS
20	59	4.09	NS	40	65	3.14	NS
30	48	3.48	NS	50	52	3.26	NS
40	41	4.40	NS	60	42	1.82	NS
50	34	1.88	NS	65	40	2.42	NS
55	30	2.47	NS	70	35	3.63	NS
60	22	4.61	NS	80	38	2.57	NS
65	10	4.69	NS	90	22	2.76	NS
Linear trend			NS	Linear trend			NS
NQO				B[a]P
0.1	33	28.54		2	46	31.06
0.15	31	16.57		3	28	69.69

 

§       = 6TG resistant mutants/10⁶viable cells 7 days after treatment

% RS =Percent relative survival adjusted by post treatment cell counts

NS    = not significant