title: Kinetics of a single administration of 74Se-selenite by oral and intravenous routes in adult humans.
abstract: The purpose of this study was to explore the fate of a single dose of labeled selenium as determined by its route of administration. Thus, the appearance of a stable isotope of selenium, administered as 74-Se-selenite, was measured in plasma, urine, and feces, with neutron activation analysis, following a 81.7 micrograms dose of 74Se-selenite given either intravenously or orally in two groups (n = 4) of healthy, young adult men, who were otherwise maintained on a diet providing a constant and adequate selenium intake. From these isotopic data, measurable parameters of urine excretion, total body retention and selenite-exchangeable metabolic pool (Se-EMP) were defined to provide a quantitative assessment of selenium metabolism in these subjects. The initial 24-hr urine excretion of the label was higher for the intravenously administered label (18.2 +/- 2.1% of dose) compared to the oral dose (11.7 +/- 2.6% absorbed dose). Thereafter, the excretion of isotope was the same for both groups. For equivalent entry of Se into the body, measured total body retention and Se-EMP were the same for both groups. These initial kinetic data suggest that the overall utilization of selenium from a single administration of selenite is comparable for the two routes of intake and that the host's selenium requirement can probably be met adequately via the intravenous administration of selenite.
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D006801:Humans; D007262:Infusions, Intravenous; D007554:Isotopes / Q000378:metabolism; D007700:Kinetics; D008297:Male; D009501:Neutron Activation Analysis; D010289:Parenteral Nutrition, Total; D012643:Selenium / Q000008:administration & dosage / Q000378:metabolism*
chemical_list: D007554:Isotopes; D012643:Selenium