Lipid Metabolism of Tumors. II. Influence of Food Lipids upon the Nature of Tumor Phospholipid.

That the nature of the lipids in the animal body is influenced by the food lipids has been reported by previous workers. The question has been raised in connection with the lipid metabolism of tumors whether or not the same can be said about the tumor lipids or to what extent they are influenced by the lipids of the food.

The tumors used in this experiment are the Jensen rat sarcoma, mouse carcinoma of Buffalo Strain 3 and the Crocker sarcoma of the mouse. The animals after the inoculation of the tumor were fed food composed of casein (30.6%), cane sugar (40.8), lipid (21.7), and salt mixture (4.9), with yeast and Oscodal as the sources of the vitamines. As the lipids of the food cod liver oil, butter, linseed oil and cocoanut oil, that is, the high and low iodine number animal and vegetable lipids, were used. After a considerably long time of feeding with these special diets, 5 to 7 weeks in case of the rat tumor and about 2 months in the other cases, the animals were killed and the iodine number of the tissue lipids was determined by the micromethod in which pyridine sulphate dibro-mide of Rosenmund and Kuhnhenn was used as a halogenizing agent and the lipids by the oxidative method of Bloor. The accuracy of this method for iodine number compared with macro-method was discussed, and the conclusion that this micromethod is available for the iodine number determination was emphasized. The phospholipid iodine number of the tissue lipids of the tumor animals was first studied. The results are shown in the following tables, and in summary it may be said that the iodine number of the phospholipid of tumors is dependent upon the food lipids like that of other tissues of the body.