Tissue distribution of intraperitoneally administered (1-->3)-beta-D-glucan (SSG), a highly branched antitumor...

Distribution of metabolically 3H-labeled (1-->3)-beta-D-glucan (3H-SSG) obtained from the culture filtrate of Sclerotinia sclerotiorum IFO 9395, in various tissues after intraperitoneal administration into ICR mice (250 micrograms/mouse) was examined. 3H-SSG was mainly detected in liver, spleen, and blood, and a negligible amount was excreted into the feces and excrement within 2 d. The significant amount of 3H-SSG remained in liver and spleen after 1 month. On the other hand, SSG was not incorporated effectively in vivo and in vitro by peritoneal exudate macrophages (0.5 microgram/1 x 10(6) M phi) Similarly in vivo, the majority of 3H-SSG distributed in spleen and liver were recovered from the non-cellular fraction and not from splenic macrophage and Kupffer cell fractions. These results suggested that (1-->3)-beta-D-glucans would not be easily incorporated by the host cells to degrade and exclude from the body even after the onset of the biological response modifier activity.