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Toxicological information

Carcinogenicity

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Administrative data

Endpoint:
carcinogenicity, other
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference
Reference Type:
publication
Title:
Suppression of Lung and Liver Carcinogenesis in Mice by Oral Administration of Myo-inositol
Author:
Nishino H, Murakoshi M, Masuda M, Tokuda H, Satomi Y, Onozuka M, Yamaguchi S, Bu P, Tsuruta A, Nosaka K, Baba M, and Takasuka N
Year:
1999
Bibliographic source:
Anitcaner Res., 19(5A):3663-3664.

Materials and methods

Test guideline
Qualifier:
no guideline available
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
not specified
Details on test material:
- Purity: Not reported

Test animals

Species:
mouse
Strain:
other: ddY (lung carcinogenesis study)
Remarks:
C3H/He (liver carcinogenesis study)
Sex:
male

Administration / exposure

Route of administration:
oral: drinking water
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
30 weeks
Frequency of treatment:
Daily
Post exposure period:
No
Doses / concentrations
Dose / conc.:
1 other: %
No. of animals per sex per dose:
12 in the lung carcinogenesis study and 12 in the control group
13 in the liver carcinogenesis study and 17 control in the control group
Control animals:
yes, concurrent no treatment
Positive control:
No

Examinations

Statistics:
No

Results and discussion

Results of examinations

Gross pathological findings:
effects observed, treatment-related
Description (incidence and severity):
Oral administration of myo-inositol resulted in a decrease of the mean number of lung tumors per mouse, to about 41% of the value for the control group (p<0.05). Myo-inositol also showed a tendency toward decreasing the percentage of tumor-bearing mice, although the difference was not statistically significant. Histologically, most tumor nodules were so called type II adenomas.

Oral administration of myo-inositol resulted in a decrease of the mean number of liver tumors per mouse, to about 10% of the number in the control group; i.e., 7.8 in the control group without myo-inositol administration, and 0.8 in myo-inositol supplemented group (p<0.01). Myo-inositol also decreased significantly the percentage of tumor-bearing mice; i.e., in the control group, 88% mice developed liver tumors, whereas in the myo-inositol-supplemented group, the incidence of liver tumors was 38% (p<0.05).

Effect levels

Dose descriptor:
other: number of tumours
Remarks on result:
other: A decrease of the mean number of lung tumors per mouse and a decrease of the mean number of liver tumors per mouse was observed.

Applicant's summary and conclusion

Conclusions:
Oral administration resulted in a decrease of the mean number of lung tumors per mouse and a decrease of the mean number of liver tumors per mouse.
Executive summary:

Oral administration of the test substance resulted in a decrease of the mean number of lung tumors per mouse, to about 41% of the value for the control group (p<0.05). It also showed a tendency toward decreasing the percentage of tumor-bearing mice, although the difference was not statistically significant. Histologically, most tumor nodules were so called type II adenomas.

 

Oral administration of the test substance resulted in a decrease of the mean number of liver tumors per mouse, to about 10% of the number in the control group; i.e., 7.8 in the control group without test substance administration, and 0.8 in test substance supplemented group (p<0.01). It also decreased significantly the percentage of tumor-bearing mice; i.e., in the control group, 88% mice developed liver tumors, whereas in the test substance-supplemented group, the incidence of liver tumors was 38% (p<0.05).