Effect of citrate infusion on urinary aluminium excretion in the rat

1. Seven pairs of rats received 1 mmol/l aluminium citrate in their drinking water 5 days before the experiments. Five additional rats were treated identically. Six rats received the same food but drank distilled water. 2. After a 6 h fast, the animal was anaesthetized, the jugular vein and femoral artery were cannulated and the bladder was catheterized, after which an intravenous infusion of Hartmann's solution containing [14C]inulin was begun. The urine was collected at 20 min intervals and 1 ml of arterial blood was obtained before the end of each collection. After at least two basal collections, the infusion was modified to contain, in addition, 5 mmol/l NaHCO3 (control) or 5 mmol/l sodium citrate (experimental). The infusion rate, constant in each pair, differed between pairs across the range 60-125 mumol/min. 3. A total of eight collections was made per animal and urine flow, glomerular filtration rate, plasma and urinary aluminium and citrate were measured. 4. Control and experimental rats had a higher mean basal plasma aluminium level (0.39 +/- 0.21 mumol/l) than the six rats receiving distilled water (0.16 +/- 0.14 mmol/l, P < 0.001). The corresponding urinary aluminium excretion rates were similar (46 +/- 31 and 47 +/- 23 pmol/min, respectively). There was no significant difference between the basal values of any variable in the control and experimental rats. No significant change was observed in any variable during the infusion of NaHCO3 (controls). Among the experimental rats, there was no significant change in urine flow, glomerular filtration rate or plasma aluminium level.(ABSTRACT TRUNCATED AT 250 WORDS)