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Toxicological information

Basic toxicokinetics

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Administrative data

Endpoint:
basic toxicokinetics, other
Type of information:
experimental study
Adequacy of study:
weight of evidence
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:
Effects of Chemical Form and Dosage on the Incorporation of Selenium into Tissue Proteins in Rats
Author:
Behne, Dietrich, et al.
Year:
1991
Bibliographic source:
American Institute of Nutrition

Materials and methods

Objective of study:
toxicokinetics
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Selenium
EC Number:
231-957-4
EC Name:
Selenium
Cas Number:
7782-49-2
Molecular formula:
Se
IUPAC Name:
selenium
Constituent 2
Reference substance name:
ambient Se
IUPAC Name:
ambient Se
Details on test material:
Elemental selenium measured, source unknown.

Test animals

Species:
rat
Strain:
Wistar
Sex:
male
Details on test animals or test system and environmental conditions:
Extremely Se-depleted male Wistar rats (Mus Rattus, Brunnthal, Germany) that were fed a diet with a Se content of only 2 ug/kg for six generations were used for the study

Results and discussion

Applicant's summary and conclusion

Conclusions:
This study was used to support the hypothesis that internal concentration levels are generally higher for doses delivered as an organic form of selenium (e.g. selenomethionine) than for the same dose delivered as an inorganic form.
Executive summary:

The publication investigated the incorporation of Se into the proteins of liver and muscle, the two main Se pools, during replenishment of Se-deficient rats with normal or large doses of 75Se-labeled selenite and selenomethionine, doses equivalent to the amounts ingested from a diet with 0.2 or 2 mg Se/kg. With the higher intake, Se levels were elevated. More Se was retained from selenomethionine than from selenite. After separation of the labeled proteins, it was apparent that the higher tissue Se contents were mainly due to nonspecific incorporation into a large number of proteins. The autors observed no differences between the two chemical forms with regard to the formation of the specific selenoproteins. The 10-fold increase in the Se supply led to a relatively small rise in the levels of these com pounds. The results indicate that after ingestion of normal amounts of selenite nearly all of the element is present in the specific selenoproteins. With increasing doses a part is also incorporated nonspecificalry into numerous other proteins. In the case of selenomethio nine, a part of the element follows the same metabolic pathways, but a percentage is also deposited directly and nonspecificalry into proteins in place of methionine.