Intestinal Transport of Selenium-75 Selenomethionine

Abstract

When measured simultaneously, selenium-75 selenomethionine accumulated identically with sulfur-35 methionine across everted hamster intestinal sacs in the presence of carrier methionine. The apparent K_m for L-methionine transport was 0.8 x 10^-3 M, as calculated from the beta emissions of S³⁵-methionine or the gamma emissions of Se⁷⁵-selenomethionine. Absorption of Se⁷⁵-selenomethionine from the gastrointestinal tract of man also occurred, with peak blood levels being reached in about 3 hours. Because of the 122-day half-life of selenium-75 and its multiple gamma emissions, Se⁷⁵-selenomethionine may serve as a tool in evaluating amino-acid absorption.