Relation of heparan sulfate content and 67Ga uptake in various tissues of rats

The distribution of 67Ga citrate in various tissues of rats at 24 hrs after i.v. injection was investigated in relation to the heparan sulfate (HS) content of the tissues. The order of 67Ga % dose per g tissue in normal rats was spleen > liver > kidney > stomach > small intestine > heart > lung > muscle > brain. This order is in good accord with that of HS content in these tissues. A comparison of the 67Ga binding affinites with mucopolysaccharides showed that HS has a characteristically high affinity for 67Ga. The binding percent (radioactivity in the precipitate as a percentage of total radioactivity in the incubation mixture) of HS with 67Ga was 95%, but other mucopolysaccharides gave values of about 20% or less HS appears to play an important role in the mechanism of 67Ga accumulation. (author)