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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
short-term repeated dose toxicity: oral
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Study period:
No data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Meets generally accepted scientific standards with acceptable restrictions.

Data source

Reference
Reference Type:
publication
Title:
Development of testicular lesions in F344 rats after treatment with boric acid.
Author:
Treinen KA & Chapin RE.
Year:
1991
Bibliographic source:
Toxicology and Applied Pharmacology 107: 325 - 355.

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: No data
Deviations:
not specified
Principles of method if other than guideline:
Six treated (9,000 ppm; equivalent to 348 mg boric acid/kg bw/day, or 61 mg B/kg bw/day) and 4 control animals per time point were killed after 4, 7, 10, 14, 21 and 28 days of exposure.
GLP compliance:
no
Limit test:
no

Test material

Constituent 1
Reference substance name:
Boric acid
IUPAC Name:
Boric acid
Details on test material:
- Name of test material: Boric acid.

Test animals

Species:
rat
Strain:
Fischer 344
Sex:
male

Administration / exposure

Route of administration:
oral: feed
Vehicle:
not specified
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
28 days.
Frequency of treatment:
Daily; food ad lib.
Doses / concentrations
Remarks:
Doses / Concentrations:
9,000 ppm; equivalent to 348 mg boric acid/kg bw/day, or 61 mg B/kg bw/day.
Basis:
nominal in diet
No. of animals per sex per dose:
Six males
Control animals:
yes, concurrent no treatment

Results and discussion

Effect levels

Dose descriptor:
LOAEL
Effect level:
348 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male
Basis for effect level:
other: Based on inhibited spermiation began from day 7 of exposure and increased in severity and number of animals affected afterwards.

Target system / organ toxicity

Critical effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
Animals were killed after 4, 7, 10, 14, 21 and 28 days of exposure. Inhibited spermiation began from day 7 of exposure and increased in severity and number of animals affected afterwards. At day 10, all exposed animals were affected, with cell death and occluded tubular lumina occurring by day 21. By day 28, there was advanced epithelial disorganisation and a significant loss of spermatocytes and spermatids from tubules at all stages of spermatogenesis. Basal testosterone level in serum was decreased from day 4 and remained lower than controls throughout the observation period. However, stimulated testosterone levels were no different between controls and exposed animals. In their discussion, the authors noted that the earliest effect produced by boric acid in this study was inhibition of spermiation (release of spermatozoa) which appeared by day 7.