Investigations of the human aluminium biokinetics with ²⁶Al and AMS

Continuing the investigations on two healthy volunteers and on two patients with renal failure, the aluminium biokinetics in humans was studied by administering oral and intravenous doses of ²⁶Al to three further healthy volunteers. Blood samples were drawn at times between 20 min and half a year after administration of the doses. The complete daily urine was collected during the first nine days, spot urine samples were taken at later times when blood samples were obtained. Creatinin renal clearances and haematocrit values were also obtained in the time period of the investigations. The ²⁶Al concentrations of the samples were measured using the Munich Tandem accelerator. An open compartment model was developed to describe the time dependences of the measured Al concentrations in blood and urine and to establish the human Al biokinetics. The model comprises stomach and duodenum for oral administration, a central compartment consisting of blood plasma and interstitial fluid with transferrin and citrate binding and three peripheral compartments which are needed to describe the time dependence for the long observation period of up to three years. Excretion of Al was mainly described from plasma citrate via the kidneys into the urine and to a lesser extent from the plasma transferrin via the liver into the stool. Time constants between the compartments, fractional intestinal absorption factors and aluminium renal clearances were derived. It was found that the sizes of two peripheral compartments of the patients with renal failure were different to those of the healthy volunteers.