Calcium carbonate

Toxicity to reproduction: other studies

Administrative data

Endpoint:

toxicity to reproduction: other studies

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:

Dietary Calcium and Lead Interact to Modify Maternal Blood Pressure, Erythropoiesis and Fetal Neonatal Growth in Rats During Pregnancy and Lactation

Author:

Bogden JD, Kemp FW, Han S, Murphy M, Fraiman M, Czerniach D, Flynn CJ, Banua ML, Scimone A, Castrovilly L and Gerter SB

Year:

1995

Bibliographic source:

Journal of Nutrition, 125: 990-1002

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Female rats were fed dietary calcium carbonate at concentrations of 0.1, 0.5 and 2.5 g/100g. After one week the animals were mated and after pregnancy was confirmed the animals were fed drinking water containing either 0 or 250 mg/L of lead.
This treatment was continued for the duration of pregnancy and for one week of lactation. Three control groups were fed the same diets without lead exposure.

GLP compliance:

not specified

Type of method:

in vivo

Test material

Test material information

Constituent 1

Reference substance name:

Calcium carbonate

EC Number:

207-439-9

EC Name:

Calcium carbonate

Cas Number:

471-34-1

Molecular formula:

CH2O3.Ca

IUPAC Name:

calcium carbonate

Details on test material:

- Name of test material (as cited in study report): Calcium carbonate, Lead acetate

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River, Kingston NY
- Age at study initiation: 12 wks
- Weight at study initiation: Not stated
- Fasting period before study: Not applicable
- Housing: Not stated
- Diet:ad libitum
- Water:ad libitum
- Acclimation period: One week


ENVIRONMENTAL CONDITIONS
No data

Administration / exposure

Route of administration:

oral: feed

Details on exposure:

No data provided on diet preparation or storage conditions

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Duplicate analysis of the diets showed mean calcium concentrations of 0.096, 0.49 and 2.34 g/100g
No data on analytical methods provided

Duration of treatment / exposure:

Exposure was for one week prior to mating, duration of pregnancy and week one of lactation

Frequency of treatment:

Continuous

Duration of test:

35-36 days (dependent on gestation period)

Doses / concentrations

Remarks:

Doses / Concentrations:
0.1, 0.5, 2.5 g calcium carbonate/100g
Basis:
nominal in diet

No. of animals per sex per dose:

0.1% group 8 animals
All other groups, 7 animals

Control animals:

other: Calcium carbonate was administered to all test animals. Water containing either lead acetate (treatment) or sodium acetate trihydrate (control)

Details on study design:

Twelve week old female rats were allowed to acclimatise to laboratory conditions for one week. During this period, modified diets containing 0.1, 0.5 and 2.5 g/100g calcium carbonate were introduced. After the acclimation period, two female rats were caged for 1 -3 days with a 13 -19 week old male rat. Female rats were examined daily for the presence of a vaginal plug and removed to a separate cage when observed. 75.4% of animals were successfully impregnated. The pregnant animals were randomly assigned to six treatment groups, two per calcium carbonate dose level of which one group was given water with lead acetate and one group was given water with sodium acetate trihydrate.

Systolic blood pressures were measured in triplicate on day 14 and 17 by tail cuff plethysmography.
Pup gender were identified on day 1 and confirmed at week 1. Pup body weights and lengths were determined on day 1 and wk 1.
Blood was obtained from dams by cardiac puncture and from the hearts of pups during dissection.
Liver, femur, kidneys and brain were sampled within 1 day of birth and one week after birth.

Laboratory analysis:
Blood samples were analysed for lead, haematocrit, free erythrocyte protoporphyrin and haemoglobin. Organs were analysed for lead, copper, iron, zinc, calcium and magnesium.
Blood lead concentrations were determined by flameless atomic absorption spectrophotometry.
Haematocrits were determined using an Adams microcentrifuge.
Haemoglobin and FEP concentrations were measured by methods reported in previous papers (Tietz 1976 and Davidow et all 1976)

Statistics:

All data was subjected to analysis of variance (ANOVA)

Results and discussion

Effect levels

Dose descriptor:

NOAEL

Remarks on result:

not determinable

Remarks:

no NOAEL identified

Observed effects

Maternal body weight was significantly lower in the group exposed to lead and 0.1% calcium carbonate. No statistical difference was observed in the mean number of pups per litter or in the gender distribution.
Animals (both dams and pups) subjected to 2.5% calcium carbonate had the lowest blood and organ lead concentrations.
Femur calcium concentrations of the pups was not influenced by treatment group
Liver iron concentrations of the dams, day-old pups and week old pups were reduced by consumption of the high calcium diet. Liver iron in the pups was also influenced by lead, with the highest concentrations occurring in pups fed the low calcium diet and exposed to lead. Significant reduction in kidney and femur iron concentrations of the dams, day old pups and one week old pups, as well as reduced brain iron concentrations in pups were also caused by consumption of the high calcium diet.

Any other information on results incl. tables

Femur calcium concentrations (dams)

% calcium carbonate	250 mg/L Lead	0 mg/L Lead
0.1	6.34±0.08 mmol/g	3.77±0.12  mmol/g
0.5	4.22±0.12 mmol/g	3.99±0.13 mmol/g
2.5	4.15±0.10 mmol/g	4.26±0.11 mmol/g

Applicant's summary and conclusion

Conclusions:

The dietary lead and calcium concentrations that were used did not interfere with the ability of the rats studied to maintain pregnancy and deliver normal pups. The reduced body weights and lengths observed in day and week old pups of dams fed the high calcium diet are likely to be partly due to the anaemia induced by the higher calcium concentrations.