Surplus acylcarnitines in the plasma of starved rats derive from the liver

Attila Sandor, Joseph Cseko, G. Kispál, Istvan Alkonyi

Research output: Contribution to journalArticle

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Abstract

The method used here to assess the contribution of liver to plasma acylcarnitine is based on the idea that in rat, shortly after administration of [3H]butyrobetaine the [3H]carnitine appearing in the plasma derives from the liver and so does the acyl moiety of [acyl-3H] carnitine. In the perchloric acid extracts of plasma and liver, the ester fraction of total carnitine was determined by enzymatic analysis and that of [3H]carnitines was determined by high performance liquid chromatography. The ester fraction of total carnitine in the plasma of fed rats was 32.6% while that of [3H]carnitines was 67.9%, 1 h following injection of [3H]butyrobetaine. For 48 h starved rats the equivalent values were 54.2 and 84.0%, respectively. 24 h after the administration of [3H]butyrobetaine, the ester content became the same in the total and [3H]carnitines. That the newly synthesized carnitine was more acylated (67.9 versus 32.6%, fed) indicates that liver exports acyl groups with carnitine as carrier. The observation that the ester fraction in the newly synthesized plasma carnitine increased with fasting (84.0 versus 67.9%) indicates that the surplus plasma acylcarnitine in fasting ketosis derives from the liver. Perfused livers, however, released carnitine with the same ester content (60-61%) whether they were from fed or fasted animals. Probably, the increased plasma [acylcarnitine] in fasting develops not by an increased ester output from the liver but by an altered handling in extrahepatic tissues.

Original languageEnglish
Pages (from-to)22313-22316
Number of pages4
JournalJournal of Biological Chemistry
Volume265
Issue number36
Publication statusPublished - Dec 25 1990

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Carnitine
Liver
Rats
Plasmas
Esters
Fasting
acylcarnitine
Liver Extracts
Ketosis
High performance liquid chromatography
Animals
High Pressure Liquid Chromatography
Tissue

ASJC Scopus subject areas

  • Biochemistry

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Surplus acylcarnitines in the plasma of starved rats derive from the liver. / Sandor, Attila; Cseko, Joseph; Kispál, G.; Alkonyi, Istvan.

In: Journal of Biological Chemistry, Vol. 265, No. 36, 25.12.1990, p. 22313-22316.

Research output: Contribution to journalArticle

Sandor, A, Cseko, J, Kispál, G & Alkonyi, I 1990, 'Surplus acylcarnitines in the plasma of starved rats derive from the liver', Journal of Biological Chemistry, vol. 265, no. 36, pp. 22313-22316.
Sandor, Attila ; Cseko, Joseph ; Kispál, G. ; Alkonyi, Istvan. / Surplus acylcarnitines in the plasma of starved rats derive from the liver. In: Journal of Biological Chemistry. 1990 ; Vol. 265, No. 36. pp. 22313-22316.
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