Mechanism of tumor and liver concentration of ¹¹¹In and ¹⁶⁹Yb: ¹¹¹In and ¹⁶⁹Yb binding substances in tumor tissues and liver

Abstract

Tumor-bearing animals were injected with ¹¹¹In- and ¹⁶⁹Yb-citrate. Tumor homogenates, from which the nuclear fraction was removed, and the mitochondrial fractions of the host livers were digested with pronase P. After digestion, the supernatants of the reaction mixtures were applied to Sephadex G-100 columns. The resultant eluates were analyzed for radioactivity, protein, uronic acid, and sialic acids. Three peaks of radioactivity were obtained by gel filtration. The first peak, eluted in the void volume, contained a species whose molecular weight exceeded 40000. The second peak consisted of substances with molecular weights of 9400–40000. Radioactivity in the third peak was liberated ¹¹¹In and ¹⁶⁹Yb. These two nuclides in the second peak were bound to acid mucopolysaccharide and/or the sulfated carbohydrate chain of sulfated glycoprotein. It was thought that the nuclides in the first peak might be bound to some acid mucopolysaccharides.

The second peak nuclides seemed to be bound to acid mucopolysaccharide that contained no uronic acids, and/or to the sulfated carbohydrate chain of sulfated glycoprotein. It was concluded that they were bound to the acid mucopolysaccharides and/or the sulfated carbohydrate chain of sulfated glycoprotein in tumor tissues and liver lysosomes.