Quantification of statin effects on hepatic cholesterol synthesis by transient (13)C-flux analysis.
The present work is the first to deal with the determination of cholesterol synthesis rates in primary rat hepatocytes using transient (13)C-flux analysis. The effects of statins on cholesterol biosynthesis and central carbon fluxes were quantified at a therapeutic concentration of 50 nM atorvastatin using carbon-labeled glutamine. The flux through the cholesterol pathway decreased from 0.27 to 0.08 mmol/l(cv)h in response to the administration of the hypolipidemic drug. Isotopic steady state was reached within 4h in the central carbon metabolism but not in the cholesterol pathway, regardless of whether atorvastatin was administered or not. Marked channeling was observed for the symmetrical tricarboxylic acid cycle intermediates, succinate and fumarate. Non-stationary (13)C-based flux identification delivers both intracellular fluxes and intermediate levels, which was for the first time utilized for investigating systems-level effects of the administered drug by quantifying the flux control of the 3-hydroxy-3-methylglutaryl-coenzyme A reductase.
Maier
Klaus
K
Institute of Biochemical Engineering, University of Stuttgart, Allmandring 31, 70569 Stuttgart, Germany.
Hofmann
Ute
U
Bauer
Alexander
A
Niebel
Anja
A
Vacun
Gabriele
G
Reuss
Matthias
M
Mauch
Klaus
K
D000818:Animals; D000924:Anticholesteremic Agents / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism; D002247:Carbon Isotopes / Q000378:metabolism; D002478:Cells, Cultured; D002784:Cholesterol / Q000096:biosynthesis*; D022781:Hepatocytes / Q000166:cytology / Q000378:metabolism; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism*; D007553:Isotope Labeling; D007700:Kinetics; D008099:Liver / Q000201:enzymology* / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar
D000924:Anticholesteremic Agents; D002247:Carbon Isotopes; D002244:Carbon; D002784:Cholesterol; D006903:Hydroxymethylglutaryl CoA Reductases