Fatty acid chain-elongation in perfused rat heart: synthesis of stearoylcarnitine from perfused palmitate.
Rat hearts perfused for up to 60 min in the working mode with palmitate, but not with glucose, resulted in substantial formation of palmitoylcarnitine and stearoylcarnitine. To test whether lipolysis of endogenous lipids was responsible for the increased stearoylcarnitine content or whether some of the perfused palmitate underwent chain elongation, hearts were perfused with hexadecanoic-16,16,16-d(3) acid (M+3). The pentafluorophenacyl ester of deuterium labeled stearoylcarnitine had an M+3 (639.4 m/z) compared to the unlabeled M+0 (636.3 m/z) consistent with a direct chain elongation of the perfused palmitate. Furthermore, the near equal isotope enrichment of palmitoyl- (90.2+/-5.8%) and stearoylcarnitine (78.0+/-7.1%) suggest that both palmitoyl- and stearoyl-CoA have ready access to mitochondrial carnitine palmitoyltransferase and that most of the stearoylcarnitine is derived from the perfused palmitate.
Kerner
Janos
J
Case Western Reserve University, School of Medicine, Department of Nutrition, Cleveland, OH 44106, United States. janos.kerner@case.edu
Minkler
Paul E
PE
Lesnefsky
Edward J
EJ
Hoppel
Charles L
CL
D000818:Animals; D002331:Carnitine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D009206:Myocardium / Q000737:chemistry / Q000378:metabolism*; D010168:Palmitates / Q000378:metabolism*; D010477:Perfusion / Q000379:methods; D051381:Rats; D011916:Rats, Inbred F344
D005227:Fatty Acids; D010168:Palmitates; C116917:acylcarnitine; D005947:Glucose; D002331:Carnitine