Distribution of 75Se and 35S in intracellular fractions of rat liver and rat kidney

Abstract Groups of rats injected with Se 75 ‐labelled sodium selenite were killed at intervals of up to 2 hr and various organs and tissues were examined for Se 75 . The livers and kidneys contained greater concentrations of Se71i than other organs examined. Counts for blood fell to a minimum at 40 min followed by a gradual increase. The pattern for the liver was the reverse of that found for blood. The soluble fraction of the sub‐cellular components isolated from liver contained the highest concentration of Se 75 per mg of protein. No other component of liver appeared to play a significant role in the incorporation of Se 75 , into the liver cell during the examination period. The light microsomes of kidney, with a peak Se 75 activity at 40 min, had a greater Se 75 ; concentration than did other kidney fractions. Twenty minutes after the simultaneous injection of S 75 ‐labelled sodium sulphate and Se 75 ‐labelled sodium selenite approximately 90% of the Se 75 in the liver and kidney sub‐cellular components was proteinbound, but the major proportion of the S35, with the exception of that in the kidney light microsomes, was readily removed by dialysis.