Gastrointestinal transfer of neptunium (V) in newborn baboons: preliminary results

To measure gastrointestinal neptunium absorption, baboons aged from 17 hours to 26 days were gavaged with an oral dose of 0.002 ug/kg of neptunium-239 nitrate. Absorption ranged from 3.71 to 0.113 per cent of the gavaged dose which was, 88 to 3 times higher than the values for adults. This range was reduced to 41 to 3 when doubtful results were discarded because of possible lung contamination. Absorption was expressed in terms of retention per animal at killing since collection of urine and faeces from neonates was not possible. For the same animals the skeleton/liver ratio of the neptunium burden rose continuously in the 26 dav-old baboon and reached twice the mean adult value