Evidence of the growth factor in mouse serum infected with Spirometra erinacei plerocercoids.

To investigate the action of the growth factor secreted by Spirometra erinacei plerocercoids, various organ weights, body weight and head-body length were measured in Snell normal and dwarf mice after injection with the serum from mice and rats. Serum from mice infected with the plerocercoids caused significant increases in the weights of the liver and spleen, in the same manner as mice infected with the plerocercoids. However, serum from rats infected with plerocercoids did not cause significant changes in these parameters. The growth factor in the serum of mice infected with plerocercoids was stable at -20 degrees C for at least 6 months and easily passed through the peritoneum.