The effect of Walker carcinoma 256 on the total lipid content of rats.

The Walker carcinoma 9256 growing in young rats may contain 920to 40 per cent of the animals' total body nitrogen at death. A large proportion of the nitrogen in the neop!asm is contributed by the body's tissues since the amount of nitrogen stored during the period of tumor growth is much smaller than the †̃ nitrogen content of the carcinoma. In fact, the rat usually has a net negative nitrogen balance during the period of tumor growth under our experimental conditions. The total nitrogen deficit (the algebraic sum of the net nitrogen bal ance and the tumor nitrogen, the latter bearing a negative sign since the progressively growing tumor sequesters nitrogen) is considerable but constitutes a highly variable fraction of the total body nitrogen (92). It is apparent then that some other factor plays an important role in producing a fatal issue. Earlier observations indicated also that deple tion of the rat's body lipid progressed with growth of the Walker tumor. It now appears that the loss of fatty substances exceeds that caused by de crease in dietary intake, a universal finding among our tumor-bearing rats. This result suggests that growth of the Walker carcinoma 9256 increases the caloric requirements of its host. Sexually mature rats derived from the Wistar strain were housed in individual, suspended, basket-type cages. They were fed the following diet: