Sources of blood glycerol during fasting

Michael D. Jensen, Visvanathan Chandramouli, William C. Schumann, Karin Ekberg, Stephen F. Previs, Sameer Gupta, Bernard R. Landau

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

To determine the source(s) of blood and very low density lipoprotein (VLDL)-triglyceride glycerol during fasting, four men ingested 2H2O from 14 to 20 h into a 60-h fast to achieve ∼0.5% body water enrichment. At 60 h of fasting, glycerol flux was measured using [2-14C]glycerol. Blood was taken for measurement of 2H enrichment at carbon 6 of glucose and at carbon 3 of free glycerol and VLDL-triglyceride glycerol. 2H enrichment of the 2 hydrogens bound to carbon 3 of VLDL-triglyceride glycerol was 105 ± 2% of the 2H enrichment of the 2 hydrogens bound to carbon 6 of glucose, indicating isotopic equilibrium between hepatic glyceraldehyde 3-P and glycerol 3-P. The 2H enrichment of the 2 hydrogens bound to carbon 3 of free glycerol was 17 ± 3% of VLDL-triglyceride glycerol, indicating that a significant percentage of free glycerol in blood originated from the hydrolysis of circulating VLDL-triglyceride or a pool of glycerol with similar 2H enrichment. Glycerol flux was 6.3 ± 1.1 μmol·kg-1·min-1. Glycerol appearing from nonadipose tissue sources was then ∼1.1 μmol·kg-1·min-1. Seven other subjects were fasted for 12, 42, and 60 h. A small percentage of glycerol in the circulation after 12 h of fasting was enriched with 2H. The enrichment of the 2 hydrogens bound to carbon 3 of free glycerol in the longer periods of fasting was ∼16% of the enrichment of the 2 hydrogens bound to carbon 6 of glucose. Therefore, as much as 15-20% of systemic glycerol turnover during fasting is not from lipolysis of adipose tissue triglyceride.

Original languageEnglish (US)
Pages (from-to)E998-E1004
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume281
Issue number5 44-5
DOIs
StatePublished - 2001

Keywords

  • Deuterated water
  • Lipolysis
  • Triglyceride
  • Very low density lipoprotein

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Physiology (medical)

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    Jensen, M. D., Chandramouli, V., Schumann, W. C., Ekberg, K., Previs, S. F., Gupta, S., & Landau, B. R. (2001). Sources of blood glycerol during fasting. American Journal of Physiology - Endocrinology and Metabolism, 281(5 44-5), E998-E1004. https://doi.org/10.1152/ajpendo.2001.281.5.e998