Tumor Lipids BIOSYNTHESIS

Labeled long chain acyl-CoA, aldehyde, and alcohol (16:0) were incubated in the peritoneal cavity of mice bearing Ehrlich ascites cells and the distribution of radioactivity in the acyl, alkyl, and alk-1-enyl moieties of various neutral lipid and phospholipid classes was compared. The results suggested the following metabolic relations. 1. Alkyl glyceryl ethers are precursors of alk-l-enyl glyceryl ethers. Alk-I-enyl acyl phosphoglycerides (plasmalogens) appear to be derived from intact alkyl acyl phosphoglycerides by biodehydrogenation. 2. Fatty acids are precursors of long chain alcohols that serve as precursors of alkyl glyceryl ethers. 3. Aldehydes are less effective precursors of plasmalogens than alcohols. They are oxidized primarily to acids and to a lesser extent are reduced to alcohols. 4. Fatty acids are elongated but the saturated acids are not desaturated to the corresponding monoenoic acids in this neoplasm. 5. Comparison of the data from the three labeled substrates suggests an interrelation that explains how each substrate was incorporated into glyceryl ethers.