GASTROINTESTINAL ABSORPTION OF ALUMINUM IN RATS USING AL-26 AND ACCELERATOR MASS-SPECTROMETRY

Using the technique of Accelerator Mass Spectrometry (AMS), Al-26 has been measured in plasma, liver, urine and bone of normal rats at 8, 24 and 48 hours after ingestion of trace amounts of Al (3.8 ng of Al-26 and 63 ng of stable Al-27), both in citrate-free and citrate-containin g solutions. Our data show that under physiological conditions, namely at normal levels of dietary intake, intestinal Al absorption is appro ximately 0.04%, and is not significantly enhanced by the presence of c itrate. Interestingly, the amount of Al retained by bone (0.02%) is co mparable to that excreted in urine during 48 h (0.02%). Our estimate o f gastrointestinal absorption is more than two orders of magnitude sma ller than that estimated by Day et al. [1991], also using Al-26, for a single human subject.