Measurements of fatty acid synthesis by incorporation of deuterium from deuterated water.

Fatty acid synthesis by perfused livers of rat is measured by using D2O as tracer. The newly synthesized, deuterium-labeled fatty acids are separated from unlabeled fatty acids by gas chromatography using glass capillary columns. The areas of the deuterium-labeled peaks are proportional to the amounts of fatty acids synthesized. The absolute amounts of the individual fatty acids synthesized are obtained by use of an internal standard. The number of deuterium atoms incorporated, as determined by mass spectrometry, is proportional to the D2O concentration of the perfusate, except at very high concentrations of D2O. The relative retention times of the newly synthesized, deuterium-labeled fatty acids are proportional to their deuterium content.