Effect of cariesogenic diet and age on selenium distribution between blood and mineralized tissues in rats

: The distribution of Se in the blood and teeth (in the jaw and femoral bones) was evaluated using a new coefficient of relative radioactivity (RRA), representing the ratio of (75)Se in the teeth (bones) and blood. Changes in all RRA were studied during 1-192 hours after intraperitoneal injection of [(75)Se]selenate in one-month-old rats receiving common fodder; a biphasic pattern of changes was observed, with peaks 6 and 48 h and lowering 24 and 192 h postinjection. The first peak was mainly due to Se adsorption on hydroxyapatite, the second to chemo-adsorption on it and Se binding to protein. In 3-month-old rats receiving common fodder the peak of all RRA was delayed to 12-48 h postinjection, the values decreasing by 192 h. The peak of specific activity (SA) of (75)Se protein in the bones was recorded 24 h and its decrease 192 h postinjection. In one-month-old rats receiving sucrose-casein diet during 2 months all RRA and SA after 6 and 12 h and part of RRA after 24 h were higher than in the control, that is, Se absorption by bones and teeth from the blood decreased.