UPTAKE OF 26-AL AND 67-GA INTO BRAIN AND OTHER TISSUES OF NORMAL AND HYPOTRANSFERRINAEMIC MICE

Aluminium uptake from blood into tissues of control and homozygous hyp otransferrinaemic (hpx/hpx) mice, following continuous intravenous inf usion of Al-26 and Ga-67, has been compared with that of gallium, a pr oposed tracer for aluminium. Al-26 uptake into tissues of control (hpx /+ and +/+) mice occurred in the order (expressed as a space): bone 46 4.7 ml 100 g(-1); renal cortex 102.9 ml 100 g(-1); liver 13.0 ml 100 g (-1); spleen 8.4 ml 100 g(-1) and brain 0.8 ml 100 g(-1). Ga-67 uptake s were similar in liver, spleen and brain, but smaller in the renal co rtex and bone, at one-third and one-fifth of the values for Al-26, res pectively. In the hypotransferrinaemic mice, uptake of Ga-67 into all tissues was increased, especially in renal cortex (ninefold) and bone (twentyfold) as compared with the controls. Increases in Ga-67 uptakes into cerebral hemisphere, cerebellum and brain stem of the hypotransf errinaemic mice were 3.8, 4.2 and 2.8 fold, respectively. Al-26 uptake into tissues of the hypotransferrinaemic mice was similar to control values except in bone where it was three times greater. Pre-treatment of control animals with the anti-transferrin receptor antibody, RI7 20 8, enhanced Ga-67 uptake in all tissues, the effect being greatest in renal cortex (tenfold) and bone (ninefold). Ga-67 uptakes into cerebra l hemisphere, cerebellum and brain stem in the mice pre-treated with R I7 208 were 6.4, 6 and 10 times greater than in untreated mice, respec tively. No influence of antibody on Al-26 uptake into mouse tissues wa s observed except in spleen where it was three times greater than in u ntreated mice. Hence, transport of aluminium and gallium into mouse ti ssues is not similar under all conditions. Non-transferrin mediated tr ansport of each metal can occur into all tissues, especially in renal cortex and bone, where gallium may be a suitable marker for aluminium.