STUDY OF THE METABOLISM OF CHOLINE AND PHOSPHATIDYLCHOLINE IN TUMORS IN-VIVO USING PHOSPHONIUM-CHOLINE

The results of an initial study on the feasibility of using the phosph onium analog of choline to follow the metabolism of phosphatidylcholin e in tumors in vivo using P-31 NMR are reported, C3H/He mice bearing a mammary carcinoma tumor on the foot pad were fed a choline-free diet supplemented with the phosphonium analog of choline. Metabolites of th is compound, including the phosphonium analogs of phosphatidylcholine, phosphocholine, glycerophosphocholine, and betaine were observed noni nvasively in vivo in tumors by P-31 NMR after 2-3 weeks of feeding, Cl earance of these phosphonium-labeled metabolites from tumors was measu red after a change to a choline-containing diet, Significant decreases were seen in the levels of the analogs of betaine (P < 0.003) and pho sphatidylcholine (P < 0.004) by Day 4. A significant increase in the l evel of authentic phosphocholine (P < 0.003) occurred over the same ti me period.