Penetration of beryllium through the placenta and its distribution in the mouse.

Penetration of beryllium through the placenta and its distribution in the organs after intravenous administration of BeCl2 in a dose of 0.1 mg/kg was studied in a series of experiments on ICR SPF mice. To trace the fate of beryllium, an isotope in the form of 7BeCl2 in an amount of 111kBq per animal was used. This dose was administered to a group of females before fertilization, on the 7th and 14th day of pregnancy, and to control animals. The animals were killed on the 18th to 19th day of pregnancy and the content of beryllium in the foetuses and its distribution in the organs of the mothers were determined by measuring activity. It has been found that beryllium penetrates through the placenta with difficulty, however, part of the dose administered circulated in the blood long enough for Be to penetrate the foetuses. Of interest is the finding that beryllium in the dose administered influenced the number of foetuses of the exposed females. This finding deserves detailed evaluation in the test of dominant lethal mutations.