Elimination of Fixed Selenium by the Rat

Abstract

Studies were conducted to determine the retention of a single injected dose of selenite by rats, and efforts were made to alter the subsequent rate of excretion of retained selenium by dietary modifications. After a single subacute injection of labeled selenite, selenium was eliminated rapidly for about 3 days, and after a period of transition a slow constant rate of loss persisted for months. The amounts of labeled selenium retained after the rapid elimination phase varied with the size of the dose, but the rate of loss thereafter did not. A series of diets fed to rats after the fixed pool had been established showed the rate of depletion from that pool to vary with selenium intake during the depletion period; loss of ⁷⁵Se was unaffected by changes in diet 1) which hasten selenium deficiency (Torula yeast); 2) which increase volatilization (high protein and methionine, or a laboratory diet); or 3) which diminish toxicity (linseed meal) except as these diets varied in selenium content.