The biodistribution of the labelled sialoglycoconjugates, ¹⁴C-sialic acid, ¹⁴C-sialyllactose and ¹⁴C-ganglioside (GM3) and their transference into the brain of rats were studied. The intravenously administrated ¹⁴C-sialic acid and ¹⁴C-sialyllactose were excreted immediately from the kidney whereas ¹⁴C-ganglioside (GM3) was accumulated in the liver. By oral administration, ¹⁴C-sialyllactose and ¹⁴C-ganglioside (GM3) were accumulated in the salivaly gland, spleen and brain. The oral administered ¹⁴C-sialyllactose was shown higher transference in to the brain than the case of intravenous administration. In the case of ¹⁴C-ganglioside (GM3), some was gradually metabolized to GM2, GD3 and GD2 the remained in brain.

It was clear that the orally administered ganglioside (GM3) was transferred into the brain, and was accumulated itself there and some metabolized.