Serum Glycoprotein Synthesis in Intact and Hepatectomized Walker 256 Tumor-Bearing Rats Following Glucosamine-1-14C Administration

Abstract

Incorporation of administered free glucosamine-1-14C into protein-bound hexosamine of the various fractions of the total serum proteins, as obtained by disc electrophoresis, has been studied in normal and in Walker 256 tumor-bearing rats, both in the intact state and following hepatectomy. Normal intact animals demonstrate greater incorporation of labeled glucosamine into a band in the transferrin zone than into the other disc electrophoretic fractions during the 3 h period of observation. The response of tumor-bearing intact animals is characterized by increased incorporation of labeled glucosamine into glycoproteins of the post-albumin zone and decreased incorporation into that in the transferrin zone in comparison with normal animals. Non-tumor-bearing hepatectomized animals fail to incorporate significant labeled glucosamine into any of the glycoprotein fractions of the serum. Tumor-bearing hepatectomized animals, on the other hand, incorporate labeled glucosamine into glycoproteins of the post-albumin zone. These studies support the suggestion that malignant tumor tissue is capable of glycoprotein synthesis and release into the circulation and indicate the gross characteristics of the tumor-produced glycoproteins.