The influence of renal insufficiency on caesium metabolism in man and rat (with a note on the Cs content of some biological standard materials).

Caesium was measured by instrumental neutron activation analysis in blood plasma and erythrocytes of persons suffering from renal disorders and in age-and sex-matched controls. The disease was at an early stage of development, the patients having creatinine plasma values below 1000 mumol/l. None of them had been dialysed. In a group of 5 patients with plasma creatinine below 250 mumol/l no changes in the blood caesium contents could be observed, but in a group of 17 with plasma creatinine between 250 and 1000 mumol/l the caesium level in the plasma was increased by 70% and in the erythrocytes by 50%, compared to the controls. An effect of renal insufficiency on the caesium metabolism was also observed in rats, in which 5/6-nephrectomy led to increases in the caesium tissue levels (muscle 30%; spleen 25%; pancreas 100%). However, as in the animals the element content in blood plasma and erythrocytes remained unchanged, it is not clear to what extent the nephrectomized rat can be used as a model in the investigation of relations between chronic uraemia and caesium metabolism. It can therefore not yet be decided whether the changes in the blood caesium levels in the patients are due to a decrease in renal excretion or are only a secondary effect of unnoticed changes in dietary habits. The increase in caesium levels suggests, however, that in the first stages of the disease the patients may receive higher radiation doses from the radioisotopes of caesium than the normal population does in the case of environmental or industrial exposure.