A comparative study of the influence of malignant tumor on host metabolism in mice and man.Evaluation of an experimental model

Abstract

Metabolic alterations in skeletal muscles and liver tissue from cancer patients were compared with corresponding alterations in mice (C‐57) with sarcoma (MCG‐101). In tumor‐bearing man and mice similar changes in enzyme activities and in protein turnover were found. Glycolytic and oxidative enzyme activities were decreased in skeletal muscle tissue. Tumor‐associated increase in lysosomal enzyme activities was found in both species. Leucine was incorporated into skeletal muscle proteins at a lower rate and into hepatic proteins at a higher rate in both species with malignant tumor. In tumor‐bearing mice ribosome profiles from skeletal muscle, heart muscle and liver showed a preponderance of slowly sedimenting units of polyribosomes suggesting that initiation of protein synthesis may be a rate limiting step. The metabolic host reactions in tumor‐bearing mice were similar to those in cancer patients implying that experimental tumors are relevant to use for analysis of mechanisms behind the development of cancer cachexia in man.