Measurement of triglyceride synthesis in humans using deuterium oxide and isotope ratio mass spectrometry

✍ Scribed by Catherine A. Leitch; Peter J. H. Jones

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 429 KB
• Volume: 20
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/bms.1200200611

✦ Synopsis

Short-term triglyceride (TG) synthesis was measured over 48 h in four healthy males from the incorporation rate of deuterium in body water into plasma TG. Subjects drank 0.7 g D,O kg-' estimated body water (99.8 atom% excess), followed by water containing 1.4 g D,O kg-' water to maintain plasma deuterium enrichment at plateau. Blood samples (20 ml) were obtained before dosing and every 4 h thereafter. Subjects self-selected three meals each day. TG from each time point were separated from plasma lipids by thin-layer chromatography and combusted to water and COz . Combustion water was vacuum distilled into Zncontainiag Pyrex tubes, reduced to hydrogen gas, and analyzed for deuterium enrichment by isotope ratio mass spectrometry. Deuterium enrichment of TG increased over the 48 h study period for all four subjects studied. Superimposed on this increase were short-term non-periodic fluctuations in enrichment reflecting dietary influx and intra-individual differences in TG metabolism. The TG fractional synthetic rate (FSR) was calculated using linear and monosxponential models. Triglyceride FSR of the subjects over the first 24 h of the study was 0.0702 f 0.0048 day-' (mean & SEM) by the linear model and 0.0728 f 0.0051 day-' by the exponential model. Deuterium enrichment reached a plateau on day 2, indicative of continuing TG synthesis in a saturated body water pool. These results are consistent with the notion of mealdependent variability in TG synthesis into a small rapid turnover plasma TG pool.