[Permeability of physiological barriers for chromium and its balance in the body when administered with water or food].

In experiments set up on albino male-rats by using Cr51 the permeability of physiological barriers to hexad stable chromium (sodium chromate), introduced with water per os in doses of 2.5 and 2250 gamma/kg was studied and the chromium balance in the rats' organism with an addition of the same doses of trivalent (chromium sulfide) chromium to the ration investigated. With all the tested additions of stable hexad chromium in water Cr51 is prevalently retained in the stomach and intestines. With an addition of 2.5 gamma/kg of stable chromium to the ration and without chromium addition to the ration it is only 7.8--9.5 per cent of the introduced Cr51 that is excreted in 4 days, the respective figures with additions of 24 gamma/kg and 2250 gamma/kg being 59.7 and 54.5 per cent. An addition of 2.5 gamma/kg of chromium to the ration is physiologically justified, for with this dose the retention in the barriers and excretion of chromium with this dose do not increase, whereas higher doses of tri- and hexavalent chromium are non-physiological, since with these doses the retention of chromium by physiological barriers sharply increases and so doses its elimination from the organism.