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Human selenite metabolism: a kinetic model
B H Patterson1, O A Levander, K Helzlsouer
1Biometry Branch, National Institutes of Health, Bethesda 20892.
The American Journal of Physiology
|September 1, 1989
Summary
This study models human sodium selenite metabolism using stable isotope tracers. The findings reveal absorption, distribution, and retention kinetics, crucial for understanding selenium
Area of Science:
- Human metabolism and pharmacokinetics
- Trace element research
- Biochemical modeling
Background:
- Sodium selenite is an essential trace element with complex metabolic pathways.
- Understanding selenium kinetics is vital for nutritional and toxicological assessments.
- Previous models lacked detailed kinetic components for human selenite metabolism.
Purpose of the Study:
- To develop a kinetic model for sodium selenite metabolism in humans.
- To quantify absorption, distribution, and retention of selenium.
- To identify distinct kinetic components influencing selenium bioavailability and toxicity.
Main Methods:
- Utilized a single oral dose of enriched stable isotope tracer 74Se in six human subjects.
- Collected and analyzed plasma, urine, and fecal samples over a 4-week period.
- Developed a compartmental model incorporating gastrointestinal absorption, enterohepatic recirculation, and tissue distribution.
Main Results:
- Approximately 84% of the administered sodium selenite dose was absorbed.
- Four distinct plasma components with mean residence times ranging from 0.2 h to 285 h were identified.
- Significant retention of selenium in tissues was observed, with an estimated 35% remaining after 90 days.
Conclusions:
- The developed model provides a detailed kinetic framework for human sodium selenite metabolism.
- Identified distinct kinetic pools are essential for differentiating selenium's nutritional and toxicological effects.
- This research is a foundational step towards understanding the various forms and functions of selenium in the human body.