thiourea; thiocarbamide

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: abstract

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Unnamed

Year:

1963

Reference 2

Reference Type:

secondary source

Title:

Thiourea

Author:

Ziegler-Skylakakis, K.

Year:

2003

Bibliographic source:

Concise international chemical assessment document 49, World Health Organization, International Programme on Chemical Safety (IPCS), Geneva

Materials and methods

Objective of study:

distribution

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Measurement of the radioactivity in fluids and tissues, paper chromatographic analysis of the chemical state of the S35, and histologic localization of the S35 by radioautography.

GLP compliance:

not specified

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

not specified

Radiolabelling:

yes

Remarks:

S35

Test animals

Species:

rat

Strain:

not specified

Sex:

not specified

Administration / exposure

Route of administration:

other: no data

Results and discussion

Main ADME results

Type:

distribution

Results:

Rapid passage of thiourea from the mother to the fetus occurred. The fetal serum concentration was lower than that of the maternal serum.

Any other information on results incl. tables

The metabolism of thiourea S35 by the developing fetal rat was studied by measurement of the radioactivity in fluids and tissues, paper chromatographic analysis of the chemical state of the S35, and histologic localization of the S35 by radioautography. Rapid passage of the thiourea from the mother to the fetus occurred. In older embryos, at 12 and 24 hr after the administration of thiourea the amniotic fluid concentration was higher than that in the maternal serum. The fetal serum concentration was lower than that of the maternal serum. The fetal thyroid to fetal serum concentration ratio began increasing on the 17th day, and by the 20th day it was 9.3 as compared with 24 for the mother. The time of appearance of the concentrating ability for thiourea S35 coincides with that for I131. The S35 was predominantly present as thiourea in the serum, amniotic fluid and urine, but some protein-bound material was also found in liver tissues, serum and amniotic fluid. Both fetal and maternal thyroid tissue had increased amounts of S3S as either sulfate or thiosulfate. The radioautographs showed concentration of grains over thyroid cells and colloid at 3 hr, but after 12 and 24 hr most of the activity was over the colloid. Some concentration of S36 was observed in fetal tracheal cartilage and in the tubules of the maternal kidney

Applicant's summary and conclusion

Conclusions:

Rapid passage of thiourea from the mother to the fetus occurred. The fetal serum concentration was lower than that of the maternal serum.