Radioiron Time-Distribution Studies at Various Ages in the Normal Male Rat

¹ From the Donner Laboratory and Radiation Laboratory, University of California, Berkeley, California

The distribution of radioiron with time has been studied in the plasma, red cells, liver, spleen, marrow, muscle and kidney in rats 15, 50, 150 and 250 days of age. The plasma clearance of Fe⁵⁹ is very rapid in the two youngest ages studied and much slower in the 150- and 250-day-old rats. Fe⁵⁹ enters the red cell most rapidly in the 15- and most slowly in the 250-day-old rats. Plasma and red cell iron turnovers were calculated. Approximately equal values for total red cell iron turnover were obtained for rats of 50, 150 and 250 days of age regardless of wide differences in body weight. The red cell iron turnover, relative to body weight was highest in the 15-day-old rats, being approximately three times that calculated for the 150- and 250-day-old rats.