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Toxicological information

Developmental toxicity / teratogenicity

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developmental toxicity
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
weight of evidence
2 (reliable with restrictions)

Data source

Reference Type:
Effects of Excess Dietary Iodine upon Rabbits, Hamsters, Rats and Swine.
R. Arrington, R. N. Taylor, Jr., C. H. Ammerman AndR. L. Shirley
Bibliographic source:
Journal of Nutrition; vol. 87, no. 4, pg. 394-398; December 1, 1965

Materials and methods

Test guideline
according to
Principles of method if other than guideline:
Long-Evans rats were fed sodium iodide atvarying intervals of time after breeding. The effect on length of gestation, parturition time, lactation and survival of young was observed.
GLP compliance:
not specified
Limit test:

Test material

Test material form:
solid: crystalline
Details on test material:
- Name of test material (as cited in study report):Sodium iodide
- Molecular formula (if other than submission substance):INa
- Molecular weight (if other than submission substance):149.89427
- Substance type:Inorganic
- Physical state:Solid

Test animals

Details on test animals and environmental conditions:
Details on test animal
- Housing:Animals were housed individually in wire cages. Prior to littering, rats were transferred to 3 X 3 mesh wire cages.
- Diet (e.g. ad libitum):Purina Laboratory Chow were provided ad libitum
- Water (e.g. ad libitum):Tap water was supplied ad libitum

Administration / exposure

Route of administration:
oral: feed
other: Diet as Purina Laboratory Chow
Analytical verification of doses or concentrations:
not specified
Details on mating procedure:
The sexually mature females were bred to normal males of the breed or strain.

Monogamous pairs of rats were mated.When breeding occurred, the time of first copulation was recorded and gestation subsequently calculated from this time to birth of the first young of the litter.Fourteen female rats which had been fed iodine and had produced but lost all young in one or more litters were subsequently re-bred after removal from dietary iodine.
- After successful mating each pregnant female was caged (how): Individually
Duration of treatment / exposure:
12 days
Frequency of treatment:
Duration of test:
From breeding to day 21 of suckling
Doses / concentrations
Doses / Concentrations:
0,150 mg/kg bw (2500 ppm)

No. of animals per sex per dose:
27 females
Control animals:
yes, concurrent vehicle


Maternal examinations:
Observations were made for length of parturition time and number of young born dead and those born live. Periodic observations were made through the lactation period for mothering instinct, evidence of lactation and survival of young.
Fetal examinations:
All surviving young from each female in the control and experimental groups were permitted to nurse through the normal suckling period.
The data was subjected to statistical analysis.Method used included ANOVA were based upon analysis of variance.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:yes

Details on maternal toxic effects:
Gestation time for rats was not affected ; however, prolonged parturition was observed in rats.No signs of the beginning of lactation were observed.

Effect levels (maternal animals)

Dose descriptor:
Effect level:
150 other: mg/kg bw
Based on:
test mat.
Basis for effect level:
other: developmental toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
An increased incidence of death in the neonates, with <10% of the young surviving for 3 days.
Weaning weight was significantly less than that of controls.Survival of the young and body weights at weaning were equal to those of controls.

Fetal abnormalities

not specified

Overall developmental toxicity

Developmental effects observed:
not specified

Applicant's summary and conclusion

The LOAEL value of orally administered sodium iodide in rats was determined to be 150 mg/kg bw resulted in incidence of death in the neonates, with <10% of the young surviving for 3 days.Weaning weight was significantly less than that of controls.
Executive summary:

Study was conducted with Long-Evans rat todetermine the effects of excess iodine intake. Females were bred to normal males,sodium iodide was added to the diet during the latter portion of gestation and the females were permitted to litter normally.

The effect of the treatment on gestation period, lactation and survival of the young was observed. Gestation time for rats was not affected ; however, prolonged parturition was observed in rats. Female rats re-bred after removal from dietary iodine produced and nursed litters normally. Incidence of death in the neonates, with <10% of the young surviving for 3 days.Weaning weight was significantly less than that of controls.

Since LOAEL is150 mg/kg bw, it is regarded that there is no developmental toxicity at concentrations lower than150 mg/kg bw when administered orally.