Transplacental passage of Al-26 from pregnant rats to fetuses and Al-26 transfer through maternal milk to suckling rats

Aluminium (Al) is toxic to the growth of fetuses and sucklings. However, th e incorporation of Al into fetuses and sucklings in the periods of gestatio n and lactation has not been well clarified because Al lacks a suitable iso tope for a tracer experiment. In this study, we used Al-26 (a radioisotope of Al with half-life of 716,000 yr) as a tracer, and measured Al-26 incorpo ration into fetuses and sucklings by accelerator mass spectrometry (AMS). T o investigate Al incorporation into fetuses through transplacental passage, Al-26 ((AlCl3)-Al-26) was subcutaneously injected into pregnant rats on da y 15 of gestation. Al-26 was also subcutaneoulsy injected into lactating ra ts from day 1 to day 20 postpartum. By day 20 of gestation, 0.2% of the 26A l injected into a pregnant rat had been transferred to the fetuses, and Al- 26 was detected in the brain and liver of the fetuses. On day 9 postpartum, high levels of Al-26 were demonstrated in the brain, liver, kidneys and bl ood of suckling rats. It is concluded that Al-26 subcutaneously injected in to pregnant rats and/or lactating rats is incorporated into their offspring through transplacental passage and/or maternal milk. (C) 2000 Elsevier Sci ence B.V. All rights reserved.