Effect of alanylglutamine-enriched infusion on tumor growth and cellular immune function in rats.

The effects of total parenteral nutrition containing alanylglutamine (Ala-Gln) on tumor growth and cellular immune response were examined in rats inoculated Yoshida sarcoma cells subcutaneously. Rats given Ala-Gln-enriched solution intravenously showed a positive nitrogen balance and the increased function of alveolar macrophages. Studies on in vitro effect of Ala-Gln on immune cells in control rats showed a significant increase in phagocytic activity of alveolar macrophages and in blastogenic response of splenocytes, respectively. In vitro experiment of Gln or Ala-Gln addition to culture medium showed a remarkable enhancement of incorporation of(3)H-thymidine into Yoshida sarcoma cells, but in vivo administration of Ala-Gln containing solution did not accelerate the growth of the same tumor as measured by changes in the weight and volume. These results suggest that Ala-Gln infusion does not stimulate tumor growth due to maintenance of some immune-enhancing effect by Gln liberated from Ala-Gln in tumor-bearing hosts.