During the period of most rapid tumor growth, rats bearing Lymphosarcoma R2788 gained more weight than did control animals, although their food consumption was almost identical. Carcass and tumor analyses showed that there was an increased percentage of water in the tumor and the carcass when compared with normal controls, sufficient to explain the increased weight gain. An equally high degree of hydration was observed in rats bearing Hepatoma 3683, although in this instance the loss of fat and body nitrogen exceeded the gain in water resulting in a loss of weight.
In confirmation of these findings, balance studies showed that in the period of most rapid tumor growth rats bearing Lymphosarcoma R2788 retained nearly the same amount of nitrogen as did control animals but an increased amount of water and sodium. Terminally, rats bearing tumors went into negative nitrogen and potassium balance. Although water retention was reduced during this period below the normal level, sodium retention persisted.
Neither the terminal loss of appetite, increased excretion of nitrogen, nor the shortened life span of the tumor-bearing rats was corrected by increasing the salt intake above that given in the standard diet.
Presented in part at the 51st Annual Meeting of the American Association for Cancer Research, Chicago, Ill., April 1960 (36).