Simultaneous tracing of {sup 76}Se-selenite and {sup 77}Se-selenomethionine by absolute labeling and speciation
- Graduate School of Pharmaceutical Sciences, Chiba University, Chuo, Chiba 260-8675 (Japan)
Nutritional selenocompounds are transformed into the assumed common intermediate selenide, which is utilized for the synthesis of selenoenzymes or transformed into methylated metabolites for excretion. Hence, selenocompound metabolites can be traced only with labeled selenium. Here we applied a new tracer method for the metallomics of biometals using simultaneous speciation of each metallome labeled with different homo-elemental isotopes to metabolism and availability of selenium. Rats were depleted of endogenous natural abundance selenium by feeding a single selenium stable isotope ({sup 82}Se-selenite) and then administered {sup 76}Se-selenite and {sup 77}Se-selenomethionine ({sup 77}Se-SeMet)simultaneously. Biological samples were subjected to quantification and speciation analysis by HPLC-ICPMS. Metabolites of the labeled {sup 76}Se and {sup 77}Se and interaction with endogenous selenium were traced and examined without interference from the corresponding endogenous natural abundance isotopes. Differences in the distribution and metabolism among organs and between the two nutritional selenocompounds were compared under exactly identical biological and analytical conditions: (1) selenite was distributed more efficiently than SeMet in organs and body fluids except the pancreas. (2) SeMet was taken up by organs in its intact form. (3) Selenium of SeMet origin was distributed selectively in the pancreas and mostly bound to a protein together with intact SeMet. (4) Selenosugars A and B but not trimethylselenonium (TMSe) were detected in the liver. (5) Selenosugar B and TMSe were detected in the kidneys.
- OSTI ID:
- 20850477
- Journal Information:
- Toxicology and Applied Pharmacology, Journal Name: Toxicology and Applied Pharmacology Journal Issue: 1 Vol. 217; ISSN TXAPA9; ISSN 0041-008X
- Country of Publication:
- United States
- Language:
- English
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