Myo-inositol

Carcinogenicity

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

Test material information

Constituent 1

Reference substance name:

Myo-inositol

EC Number:

201-781-2

EC Name:

Myo-inositol

Cas Number:

87-89-8

Molecular formula:

C6H12O6

IUPAC Name:

cyclohexane-1,2,3,4,5,6-hexol

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).