Lipid Metabolism of Tumors.

Abstract

As a preliminary report on the lipid metabolism of tumors, of which little is known, lipids of the transplanted carcinoma of the mouse as well as malignant and benign human tumors were analyzed. The total lipids and phospholipids were determined by Bloor's oxidative method, cholesterol and other unsaponifiable substance by the oxidative method with some modifications. Neutral fat was calculated by the subtraction of phospholipid and cholesterolester fatty acid from total fatty acid. The micro-oxidative determination of cholesterol of Okey was modified in that the cholesterol digitonide after saponification and washing on the glass filter was dissolved by hot absolute alcohol, the solution filtered then evaporated to dryness to get rid of alcohol and the residue oxidized. The total unsaponifiable substance was obtained as follows: The lipid solution was saponified with sodium alcoholate, then acidified and extracted with petroleum ether. The petroleum ether was then added to equal volumes of absolute alcoholic sodium alcoholate and water whereby the fatty acids are separated as soap in the alcohol-water while the unsaponifiable remains in the petroleum ether. The unsaponifiable substance in the petroleum ether is recovered by evaporation, determined by oxidation and calculated as cholesterol.

The average value of lipid analysis in tumors is tabulated: (Lipid content is expressed as gm. per 100 gm. dry tissue.)

The high lipid content of malignant tumors is notable. The high phospholipid content in malignant tumors as compared with benign tumors seems to be of particular interest. The water content of tumors is generally high as has been reported, little difference was found in the content of residual or unknown unsaponifiable substance. The experiments are being continued.