INCORPORATION OF A PHOSPHONIUM ANALOG OF CHOLINE INTO THE RAT-BRAIN AS MEASURED BY MAGNETIC-RESONANCE SPECTROSCOPY

A clear understanding of choline metabolism is important in our goal t o modify demyelination and remyelination in multiple sclerosis. To dev elop a technique capable of measuring metabolic changes in the brain, we have studied the incorporation of a phosphonium analogue of choline (P-choline) in tissue extracts of rats. After feeding adult rats a ch oline-deficient diet supplemented with P-choline, the analogue was not detectable by in vivo volume-localized H-1 spectroscopy. However, in vitro P-31 measurements of brain extracts revealed an 11% incorporatio n of P-choline into phosphatidylcholine. We report that P-choline inco rporates preferentially into the lipid pool over the lipid precursor p ool and we provide evidence that the choline peak resolved by in vivo H-1 spectroscopy is only composed of small molecular weight choline-co ntaining compounds.