TISSUE ALUMINUM DISTRIBUTION IN GROWING, MATURE AND AGING RATS - RELATIONSHIP TO CHANGES IN GUT, KIDNEY AND BONE METABOLISM

The purpose of this study was to determine whether accumulation and tu rnover of aluminium differed among growing (2 month old), mature (8 mo nth old) and ageing (19 month old) rats and assess whether these diffe rences could be ascribed to physiological changes with age. One day af ter a large oral dose (0.8 mmol Al in 0.75 M citrate) growing rats had the highest concentrations of aluminium in tibias, whereas ageing rat s had the highest concentrations of aluminium in kidneys. The half-lif e of aluminium in tibias (38 v. 58 v. 173 days in growing, mature and ageing rats, respectively) and kidneys (9 v. 12 v. 16 days) lengthened with age. According to stepwise multiple regression analysis, 73% var iation in tibia aluminium concentrations was explained by final body w eight of rats, length of time after dosing, tibia weights, haematocrit s, urinary hydroxyproline excretion, ulna calcium concentrations, and urinary creatinine excretion but 57% variation in kidney aluminium con centrations was explained by length of time after dosing and feed inta ke. Although age, per se, was a significant predictor of spleen and li ver aluminium concentrations, the measured changes in gut, kidney, bon e and mineral metabolism were less predictive of aluminium concentrati ons in livers and spleens than in bone.