A study of the content of zinc in white rats erythrocytes after X-irradiation

The changes in the red cell zinc content of rats between the 2nd and the 24th hour after exposure to 500 r X-rays were studied. The zinc content in packed red cells was determined by polarography. The mean zinc content in 31 normal animals amounted to 12.96 +- 3.75 mcg/gram fresh weight of packed red cells. The content of zinc increased to 124.6 per cent of the normal level on the second hour after irradiation, dropped to 61.8 per cent on the 19th hour, then gradually started to increase reaching a maximum on the third day. There was a drop again after the third day and on the seventh day the level was 62.6 per cent of the normal one. A gradual return to normal was observed during the next few days. Correlation of these results with changes of the carbonate hydrolysis index in red cells of rats exposed to the same dose revealed a reverse relationship between them, thus calling in question the possibility to judge the amount of carbonate hydrolysis from a determination of red cell zinc content. The changes in the zinc content during the first days after irradiation are attributed to the redistribution of microelements and increased permeability of the tissue barrier after the radiation insult. The results after the seventh day are discussed against the background of a regenerating erythropoiesis. (Ch.K.)