EFFECTS OF ALUMINUM ON THE MINERAL METABOLISM OF RATS IN RELATION TO AGE

The present study was conducted to assess in rats the effects of chron ic aluminium (Al) exposure on calcium (Ca), magnesium (Mg), manganese (Mn), copper (Cu), zinc (Zn) and iron (Fe) accumulation and urinary ex cretion in relation to the age of the animals. Male young (21 day old) , adult (8 months), and old (16 months) rats were orally exposed to 0, 50, or 100 mg Al/kg/day for a period of 6.5 months. Urinary levels of essential elements were determined after 3 and 6.5 months of exposure , whereas tissue Ca, Mg, Mn, Cu, Zn and Fe concentrations were examine d after 6.5 months of Al administration. A number of age-related chang es in tissue accumulation and urinary excretion of essential elements following chronic exposure to Al were found. Concentrations of essenti al elements in most tissues of young Al-exposed rats were generally lo wer than those of adult and old rats. The highest levels of essential elements were found in old animals. Liver, testes and spleen were the tissues that showed the most remarkable increases in relation to the l evels found in those tissues of young rats. Adult rats showed a patter n comparable to that of old animals for mineral metabolism in brain, w hereas in bone and testes the pattern of accumulation was closer to th at of young rats. While the urinary levels of Ca were generally reduce d in the Al-exposed groups, no Al-associated changes were noted for Mg , Mn, Cu and Zn. In turn, after 6.5 months of Al administration Fe exc retion was increased in Al-treated adult and old rats. The results of this study suggest that early stages of life cycle should be of specia l concern for Al-induced changes in the metabolism of essential elemen ts.