TY - JOUR AU - Evans, AM AU - Fornasini, G TI - Pharmacokinetics of L-carnitine JF - CLINICAL PHARMACOKINETICS J2 - CLIN PHARMACOKINET VL - 42 PY - 2003 IS - 11 SP - 941 EP - 967 PG - 27 SN - 0312-5963 DO - 10.2165/00003088-200342110-00002 UR - https://m2.mtmt.hu/api/publication/24658284 ID - 24658284 N1 - Export Date: 2 August 2022 CODEN: CPKND LA - English DB - MTMT ER - TY - JOUR AU - Farkas, Viktória AU - Bock-Marquette, Ildikó AU - Cseko, J AU - Sándor, Attila TI - Inhibition of carnitine biosynthesis by valproic acid in rats--the biochemical mechanism of inhibition JF - BIOCHEMICAL PHARMACOLOGY J2 - BIOCHEMIC PHARMACOL VL - 52 PY - 1996 IS - 9 SP - 1429 EP - 1433 PG - 5 SN - 0006-2952 DO - 10.1016/S0006-2952(96)00507-2 UR - https://m2.mtmt.hu/api/publication/1426930 ID - 1426930 AB - The anticonvulsive drug, valproic acid (VPA), inhibits the biosynthesis of carnitine, and may contribute in this way to carnitine deficiency associated with VPA therapy. The conversion of [3H]-butyrobetaine into [3H]-carnitine was determined 60 min following a single intraperitoneal (i.p.) dose of 1.2 mmol/kg VPA in rats. The fraction of radioactivity found in [3H]-carnitine in the liver decreased from 63.2 +/- 1.50% to 39.2 +/- 1.11% (mean +/- SEM). Total carnitine in the liver also decreased, whereas the precursor butyrobetaine increased from 5.01 +/- 0.71 nmol/g to 8.22 +/- 0.82 nmol/g (mean +/- SEM). VPA also exhibited a dramatic effect on the conversion of an unlabeled loading amount of butyrobetaine. The increment in total carnitine caused by butyrobetaine in liver was reduced from 161 +/- 15.4 nmol/g to 53.2 +/- 5.11 nmol/g (mean +/- SEM). These data prove that VPA reduces the flux through butyrobetaine hydroxylase (EC 1.14.11.1.). The drug in vitro, however, did not inhibit the enzyme directly. Searching for the mechanism of action, we found that VPA decreased the level of alpha-ketoglutarate (alpha-KG; a cofactor of butyrobetaine hydroxylase) from 73.5 +/- 2.90 nmol/g to 52.9 +/- 2.2 nmol/g (mean +/- SEM) in the liver. The level of 1-glutamate showed a rather dramatic decrease in the liver. Moreover, alpha-KG proved to have a protective role against VPA in the [3H]-butyrobetaine conversion experiment. LA - English DB - MTMT ER - TY - JOUR AU - Kispál, Gyula AU - Sümegi, Balázs AU - Dietmeier, K AU - Bock-Marquette, Ildikó AU - Gajdos, G AU - Tomcsányi, T AU - Sándor, Attila TI - Cloning and sequencing of a cDNA encoding Saccharomyces cerevisiae carnitine acetyltransferase. Use of the cDNA in gene disruption studies JF - JOURNAL OF BIOLOGICAL CHEMISTRY J2 - J BIOL CHEM VL - 268 PY - 1993 IS - 3 SP - 1824 EP - 1829 PG - 6 SN - 0021-9258 UR - https://m2.mtmt.hu/api/publication/1060968 ID - 1060968 N1 - Export Date: 27 January 2024; CODEN: JBCHA LA - English DB - MTMT ER - TY - JOUR AU - Sándor, Attila TI - Radioisotopic carnitine assay using Dowex 50 cation exchanger resin. JF - EUROPEAN JOURNAL OF CLINICAL CHEMISTRY AND CLINICAL BIOCHEMISTRY J2 - EUR J CLIN CHEM CLIN VL - 29 PY - 1991 IS - 5 SP - 347 EP - 349 PG - 3 SN - 0939-4974 UR - https://m2.mtmt.hu/api/publication/1426935 ID - 1426935 N1 - Note AB - At termination of the known radioisotopic carnitine assay the incubating mixture was applied to a column of Dowex 50 W x 8 (H+) resin. The [1-14C]acetyl-L-carnitine formed during the incubation bound to the resin, while the excess of [1-14C]acetyl-CoA was washed out with water. Then the radioactivity from the resin was eluted with NH4OH and water into counting vials. The assay is handy, takes much less (one-eights) resin than the known radioisotopic methods and the blank value is insensitive to sample volume. LA - English DB - MTMT ER - TY - JOUR AU - Sándor, Attila AU - Cseko, J AU - Kispál, Gyula AU - Alkonyi, István TI - Surplus acylcarnitines in the plasma of starved rats derive from the liver. JF - JOURNAL OF BIOLOGICAL CHEMISTRY J2 - J BIOL CHEM VL - 265 PY - 1990 IS - 36 SP - 22313 EP - 22316 PG - 4 SN - 0021-9258 UR - https://m2.mtmt.hu/api/publication/1426936 ID - 1426936 N1 - Export Date: 27 January 2024; CODEN: JBCHA AB - 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. LA - English DB - MTMT ER -