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Toxicological information

Carcinogenicity

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Administrative data

Endpoint:
carcinogenicity: oral
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable, well documented publication.

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Tumorigenic effects of chronic administration of benzylhydrazine dihydrochloride and phenylhydrazine hydrochloride in Swiss mice
Author:
Toth B. and Shimizu H.
Year:
1976
Bibliographic source:
Z. Krebsforsch. 87, 267-273; cited in WHO 2000, Phenylhydrazine. CICAD 19, Wissenschaftliche Verlagsgesellschaft mbH
Reference Type:
secondary source
Title:
Unnamed
Year:
1994
Reference Type:
secondary source
Title:
Concise International Assessment Document 19: Phenylhydrazine
Author:
WHO
Year:
2000
Bibliographic source:
Wissenschaftliche Verlagsgesellschaft mbH, Stuttgart, ISBN 92 4 153019 7; ISSN 1020-6167

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 451 (Carcinogenicity Studies)
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): phenylhydrazine hydrochloride (PH)
- other: purchased from Eastman Organic Chemicals, Rochester, N.Y.

Test animals

Species:
mouse
Strain:
Swiss
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: from the colony randomly bred by the authors laboratory since 1951
- Age at study initiation: 5 weeks (36 days)
- Weight at study initiation: no data
- Fasting period before study: no data
- Housing: plastic cages with granular cellulose bedding, separated according to sex in groups of ten animals
- Diet: Wayne lab-blox diet in regular pellets (Allied Mills, Inc., Chicago, Illinois), ad libitum
- Water: tap water ad libitum

ENVIRONMENTAL CONDITIONS
- no data

Administration / exposure

Route of administration:
oral: drinking water
Vehicle:
water
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
- Rate of preparation of solutions (frequency): thrice weekly;
- Storage: The solutions were stored in brown bottles because of the possible light sensitivity of the chemical.

Analytical verification of doses or concentrations:
no
Duration of treatment / exposure:
lifelong
Frequency of treatment:
daily
Post exposure period:
no
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
0.08, 0.06, 0.04, 0.02, and 0.01%
Basis:
nominal in water
for 35 days
Remarks:
Doses / Concentrations:
0.01%
Basis:
nominal in water
life span; average daily intake of PH, calculated from average daily water consumption: 0.63 mg (females); 0.81 mg (males). Estimated exposure, based on an assumed average bw of 25 g: approx. daily exposure of 25 mg/kg for females and 32 mg/kg for males.
No. of animals per sex per dose:
50
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: Toxicity studies were carried out with the chemical prior to the chronic experiment. Five dose levels of PH such as 0.08, 0.06, 0.04, 0.02, and 0.01% were administered in the drinking water for 35 days to Swiss mice.
Taking into account four parameters, survival rates, body weights, chemical consumption figures and histological changes, the 0.01% in the PH-treated were found to be suitable for the lifelong treatments.
Positive control:
no data

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: no data

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: no data

Sacrifice and pathology:
GROSS PATHOLOGY: Yes;
All organs were examined macroscopically and were fixed in 10 % buffered formalin.

HISTOPATHOLOGY: Yes;
Histological studies were done on the liver, spleen, kidney, bladder, thyroid, heart, pancreas, testis, brain, nasal turbinate and at least four lobes of the lungs of each mouse as well as on those organs showing gross pathologic changes. Sections from these tissues were stained routinely with hematoxylin and eosin.
Other examinations:
no data
Statistics:
no data

Results and discussion

Results of examinations

Details on results:
CLINICAL SIGNS AND MORTALITY
PH-treatment reduced the survival rates in both sexes, when compared with the untreated controls. The survival time of 50 % of the animals was 95 weeks for the control and 85 weeks for the treatment group.

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study):
The average daily water consumption containing PH per animal was 6.3 ml for the females and 8.1 ml for the males.

GROSS PATHOLOGY AND HISTOPATHOLOGY: NEOPLASTIC
• Lung Tumors:
8 (16 %) of the females developed such neoplasms. Out of these females, 6 mice had 8 adenomas and 2 had 2 adenocarcinomas. Their
average age at death was 87 weeks, the first was found at the 62nd week and the last at the 115th week of age.
In the PH-treated males, 5 (10 %) mice developed 5 adenomas. Their average age at death was 94 weeks, the first was found at the
59th week and the last at the 115th week of age.
Macroscopically and histologically, these lung lesions appeared to be similar to those found in this mouse strain and described earlier (Toth
et al., 1964; Toth and Shimizu, 1974).

• Blood Vessel Tumors:
In the PH-treated mice, 11 (22 %) females developed blood vessel tumors. Out of these, 5 had angiosarcomas in livers, 5 mice had angiomas in livers and 1 mouse developed angiomas in liver and ovary. Their average age at death was 71 weeks, the first was observed at the 47th week and the last at the 103rd week of age.
In the males of this group, 10 (20 %) mice developed such tumors. Out of these, 3 had angiosarcomas in livers, 1 had angiosarcomas in liver and spleen, 1 developed angiosarcoma in spleen, 4 had angiomas in livers, and 1 had angiomas in liver and spleen.
Their average age at death was 87 weeks, the first was found at the 58th week and the last at the 115th week of age.
Grossly and histologically, these neoplasms appeared similar to those found with other substituted hydrazines (Toth and Wilson, 1971; Toth, 1973).
The incidence of blood vessel tumors increased from 5 to 22 % in females and from 6 to 20 % in males, as compared with the controls and is significantly higher in the PH-treated females (P<0.008) and males (P<0.02) compared with the untreated groups.

• Malignant Lymphomas:
In PH-treated animals, 10 (20 %) females developed 4 lymphocytic type and 6 histiocytic type of malignant lymphomas. Their average age at death was 85 weeks, the first was found at the 66th week and the last at the 100th week of age.
In the males of this group, 6 (12 %) had malignant lymphomas, 2 histiocytic type and 4 unclassifiable (because of advanced decomposition). Their average age at death was 85 weeks, the first was observed at the 75th week and the last at the 96th week of age.
Grossly and microscopically, these tumors were similar to those found and described earlier in this mouse strain (Toth et al., 1963, J. nat. Cancer Inst. 30, 723 -741.

• Other Tumors:
A few other types of tumors were also observed in the treated animals. Because in each group, only a few were seen, their appearances can not be attributed to the treatments.

• Tumors in untreated controls:
The incidences and description of spontaneous tumors in the controls were published earlier (Toth and Shimizu, 1974, J. nat. Cancer Inst. 52, 241-251).

Histopathologically, tumors were classified as adenomas and adenocarcinomas of lungs, angiomas and angiosarcomas of blood vessels and malignant lymphomas, of both lymphocytic and histocytic types.

OTHER REMARKS
One of the main possible explanations for some of the lower tumor incidence i.e. in lungs and lymphoreticular tissue in the treated animals, as compared to controls is that the treatments substantially shortened survival rates. Thereby, some of the low tumor incidences were due to the fact that many animals died of splenomegaly. Accordingly, the tumors with long latencies did not have the chance to appear in animals.

Effect levels

open allclose all
Dose descriptor:
dose level:
Effect level:
25 mg/kg bw/day
Sex:
female
Remarks on result:
other: Effect type: carcinogenicity (migrated information)
Dose descriptor:
dose level:
Effect level:
32 mg/kg bw/day
Sex:
male
Remarks on result:
other: Effect type: carcinogenicity (migrated information)

Any other information on results incl. tables

Table 1: Tumor distribution in phenylhydrazine HCl (PH)-treated swiss mice.

 

 

Total number of animals

Animals with tumors of the: 

 

 

 

 

 

 

 

 

 

Lung (tumor incidence)

 

Blood vessels 

 

Malignant lymphomas

 

Other organsb

 

Sex

No

%

age at deatha

 

No

%

age at deatha

 

No

%

age at deatha

 

 

0.01 % PH in drinking water daily for life (= 0.63 mg/day)c

Females

49

8

16

87 (62 - 115)

 

11

22

71 (47 - 103)

 

10

20

85 (66 - 100)

 

1 Hepatoma (81),

1 Adenocarcinoma of breast (93),  

1 Adenocortical adenoma (113),

1 Adenoma of glandular stomach (88)

0.01 % PH in drinking water daily for life (= 0.81 mg/day)d

Males

49

5

10

94 (59 - 115)

 

10

20

87 (58 - 115)

 

6

12

85 (75 - 96)

 

2 Hepatoma (76, 115),

1 Adenocarcinoma of cecum (115),

1 Malignant histiocytoma (101)

Control, historical

Females

99

21

21

 

 

 

5

 

 

24

24

 

 

17 different adenomas and carcinomas (17 %)

Control, historical

Males

99

5

10

 

 

10

20

 

 

6

12

 

 

13 different adenomas and carcinomas (13 %)

aAverage and range; bAge at death given in parentheses;ctotal dose after 90 weeks: ca 400 mg;dtotal dose after 90 weeks: ca 500 mg;

The survival time of 50 % of the animals was 95 weeks for the control and 85 weeks for the treatment group.

Applicant's summary and conclusion