title: Monitoring vitamin E pools in sheep tissue and plasma after intravenous dosing of radiotocopherol.
abstract: The fate of radiotocopherol was studied in plasma and tissues of sheep at various intervals after injection of single intravenous doses of 3H-labelled D-alpha-tocopherol. Plasma samples were taken at regular intervals after dosing and selected tissues were taken from all sheep after slaughter and assayed for radioactivity and D-alpha-tocopherol. Sheep were killed in groups of five at 24, 72, 96, 272 and 432 h post-dosing. Plasma profiles were characterized as a sum of three exponential terms. A principal component analysis of tissue concentrations was carried out to identify tissues with parallel profiles of log (disintegrations/min per microgram) over time. Five groups of tissues with distinct uptake and elimination processes were identified. The D-alpha-tocopherol in the liver and heart appeared to be consistent with the post-distributive kinetics of a highly perfused shallow compartment, while lung kinetics appeared to reflect a non-linear kinetic process. The third group, which included the spleen, neck brachiocephalicus muscle and pancreas, had depletion rates parallel to those of plasma for 24-272 h, but slower decreases than plasma over 272-432 h. Hip gluteus muscle and kidney comprised a fourth group, with depletion parallel to plasma rates for 24-96 h but progressively slower than plasma decreases over 96-272 h. Adrenal kinetics resembled the fourth group, but had a more rapid decrease in specific activities over 24-72 h.
authors.affiliation: Drugs Directorate, Health and Welfare Canada, Ottawa, Ontario.
authors.forename: K
authors.initials: K
authors.lastname: Karpinski
authors.forename: M
authors.initials: M
authors.lastname: Hidiroglou
mesh_terms: D000818:Animals; D007275:Injections, Intravenous; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D012756:Sheep / Q000378:metabolism*; D013997:Time Factors; D014018:Tissue Distribution; D014316:Tritium; D014810:Vitamin E / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D014316:Tritium; D014810:Vitamin E