Urinary trimethylselenonium excretion by the rat: effect of level and source of /sup 75/Se
The purpose of this study was to explore in rats the urinary metabolites of selenium (Se), by using (/sup 75/Se)selenomethionine, (/sup 75/Se)selenocystine, and (/sup 75/Se)selenite, and to assess the effects of low and high levels of Se intake on trimethylselenonium ion (TMSe) excretion in urine. Male adult rats were adapted for 6 weeks to a commercial rat laboratory stock diet (0.25 ppm Se). They were then starved for 24 hours and given an oral dose of either low (16 micrograms Se/kg body weight) or high (1500 micrograms Se/kg body weight) Se as the test Se compounds. Appearance of radioactivity in TMSe and non-TMSe Se metabolites in urine was monitored for 48 hours. About 40% of the /sup 75/Se dose was excreted in urine. TMSe was the major urinary Se metabolite (57-69% of urinary /sup 75/Se and 16-25% of oral /sup 75/Se dose) at high, and a minor urinary Se metabolite (10% of urinary /sup 75/Se and 3-4% of oral /sup 75/Se dose) at low dose levels of Se and for all three Se test compounds. At least 80% of urinary /sup 75/Se and 26-42% of the orally administered /sup 75/Se were excreted as non-TMSe Se metabolites in urine under the latter condition. It is hypothesized that at a requirement intake of Se either a trace or no TMSe is excreted in urine, and it becomes a major excretory metabolite of Se when the dietary trace mineral intake exceeds a requirement level, probably serving as a means of detoxification.
- Research Organization:
- Laboratory of Human Nutrition, Department of Nutrition and Food Science, Massachusetts Institute of Technology, Cambridge
- OSTI ID:
- 6217684
- Journal Information:
- J. Nutr.; (United States), Vol. 113:2
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
SELENIUM
METABOLISM
SELENIUM 75
CYSTINE
DIET
EXCRETION
METABOLITES
METHIONINE
RADIONUCLIDE KINETICS
RATS
TRACER TECHNIQUES
URINE
AMINO ACIDS
ANIMALS
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BODY FLUIDS
CARBOXYLIC ACIDS
CLEARANCE
DAYS LIVING RADIOISOTOPES
DISULFIDES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
LIPOTROPIC FACTORS
MAMMALS
MATERIALS
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
RADIOISOTOPES
RODENTS
SELENIUM ISOTOPES
SEMIMETALS
VERTEBRATES
WASTES
560305* - Chemicals Metabolism & Toxicology- Vertebrates- (-1987)
550501 - Metabolism- Tracer Techniques