Quantification of muscle triglyceride synthesis rate requires an adjustment for total triglyceride content

Rabia Asghar, Maria Chondronikola, Edgar L. Dillon, William J. Durham, Craig Porter, Zhanpin Wu, Maria Camacho-Hughes, Clark R. Andersen, Heidi Spratt, Elena Volpi, Melinda Sheffield-Moore, Labros Sidossis, Robert R. Wolfe, Nicola Abate, Demidmaa R. Tuvdendorj

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Intramyocellular triglyceride (imTG) in skeletal muscle plays a significant role in metabolic health, and an infusion of [13C16]palmitate can be used to quantitate the in vivo fractional synthesis rate (FSR) and absolute synthesis rate (ASR) of imTGs. However, the extramyocellular TG (emTG) pool, unless precisely excised, contaminates the imTG pool, diluting the imTG-bound tracer enrichment and leading to underestimation of FSR. Because of the difficulty of excising the emTGs precisely, it would be advantageous to be able to calculate the imTG synthesis rate without dissecting the emTGs from each sample. Here, we tested the hypothesis that the ASR of total TGs (tTGs), a combination of imTGs and emTGs, calculated as “FSR × tTG pool,” reasonably represents the imTG synthesis. Muscle lipid parameters were measured in nine healthy women at 90 and 170 min after the start of [13C16]palmitate infusion. While the measurements of tTG content, enrichment, and FSR did not correlate (P > 0.05), those of the tTG ASR were significantly correlated (r = 0.947, P < 0.05). These results demonstrate that when imTGs and emTGs are pooled, the resulting underestimation of imTG FSR is balanced by the overestimation of the imTG content. We conclude that imTG metabolism is reflected by the measurement of the tTG ASR.

Original languageEnglish (US)
Pages (from-to)2018-2024
Number of pages7
JournalJournal of Lipid Research
Volume59
Issue number10
DOIs
StatePublished - 2018

Keywords

  • In vivo muscle triglyceride synthesis
  • Skeletal muscle lipid metabolism
  • Stable isotope tracers

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology
  • Cell Biology

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