The gastrointestinal absorption of 63Ni and 95Nb in adult and neonatal rats: effect of the chemical form administered

The gastrointestinal absorption of 63Ni and 95Nb has been determined in adult and neonatal rats after administration as various chemical forms. For 63Ni, f1 was determined as (4.3 ± 1.4) x 10-2, (5.1 ± 2.1) x 10-2 and (3.3 ± 1.5) x 10-2, for the citrate, oxalate and chloride forms, respectively. For 95Nb, the corresponding f1 values were (1.25 ± 0.37) x 10-2, (0.37 ± 0.15) x 10-2 and (0.24 ± 0.07) x 10-2, respectively. When radionuclides were administered to 1 day old animals, the retention increased by factors of up to 40 and 200 for 63Ni-chloride and 95Nb-oxalate, respectively. All these results are discussed with respect to the ICRP recommendations. (author)