Abstract
Hydroxybutyrylcarnitine (HB-carnitine) is a metabolite that has been associated with insulin resistance and type 2 diabetes mellitus. It is currently unknown whether HB-carnitine can be produced from D-3-hydroxybutyrate (D-3HB), a ketone body; but its formation from L-3-HB-CoA, a fatty acid beta-oxidation intermediate, is well established. We aimed to assess which stereoisomers of 3-HB-carnitine are present in vivo. Ketosis and increased fatty acid oxidation were induced in 12 lean healthy men by a 38-hour fasting period. The D-3HB kinetics (stable isotope technique) and stereoisomers of muscle 3-HB-carnitine (high-performance liquid chromatography/ultra-performance liquid chromatography-tandem mass spectrometry) were measured. Muscle D-3HB-carnitine content was much higher compared with L-3HB-carnitine. In addition, muscle D-3HB-carnitine correlated significantly with D-3-HB production. Following the finding that a ketone body can be converted into a carnitine ester in vivo, we show in vitro that D-3-HB can be converted into HB-carnitine (ketocarnitine) via an acyl-CoA synthetase reaction in several tissues including human muscle. During fasting, HB-carnitine in muscle is derived mainly from the ketone body D-3HB. The role of D-3HB-carnitine synthesis in metabolism remains to be elucidated.
Original language | English |
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Pages (from-to) | 966-973 |
Number of pages | 8 |
Journal | Metabolism-Clinical and Experimental |
Volume | 61 |
Issue number | 7 |
DOIs | |
Publication status | Published - Jul 2012 |
Keywords
- FATTY-ACID OXIDATION
- KETONE-BODIES
- MASS-SPECTROMETRY
- LIPID-SYNTHESIS
- RAT-LIVER
- ACYL-COA
- CARNITINE
- L-(&)-3-HYDROXYBUTYRATE
- L-3-HYDROXYBUTYRATE
- QUANTIFICATION