Journal article

Publication year: 2014

Journal: BMC Pharmacology and Toxicology

Volume number: 15

ISSN: 2050-6511

Open access status: Gold

DOI Link: https://doi.org/10.1186/2050-6511-15-37

Publisher: BioMed Central

Abstract: 
Background: Activation of peroxisome proliferator-activated receptor (PPAR)alpha and PPAR delta causes an elevation of tissue carnitine concentrations through induction of genes involved in carnitine uptake [novel organic cation transporter 2, (OCTN2)], and carnitine biosynthesis [gamma-butyrobetaine dioxygenase (BBD), 4-N-trimethyl-aminobutyraldehyde dehydrogenase (TMABA-DH)]. Recent studies showed that administration of the plasma lipid-lowering drug niacin causes activation of PPAR alpha and/or PPAR delta in tissues of obese Zucker rats, which have a compromised carnitine status and an impaired fatty acid oxidation capacity. Thus, we hypothesized that niacin administration to obese Zucker rats is also able to improve the diminished carnitine status of obese Zucker rats through PPAR-mediated stimulation of genes involved in carnitine uptake and biosynthesis.
Methods: To test this hypothesis, we used plasma, muscle and liver samples from a recent experiment with obese Zucker rats, which were fed either a niacin-adequate diet (30 mg niacin/kg diet) or a diet with a pharmacological niacin dose (780 mg niacin/kg diet), and determined concentrations of carnitine in tissues and mRNA and protein levels of genes critical for carnitine homeostasis (OCTN2, BBD, TMABA-DH). Statistical data analysis of all data was done by one-way ANOVA, and Fisher's multiple range test.
Results: Rats of the obese niacin group had higher concentrations of total carnitine in plasma, skeletal muscle and liver, higher mRNA and protein levels of OCTN2, BBD, and TMABA-DH in the liver and higher mRNA and protein levels of OCTN2 in skeletal muscle than those of the obese control group (P < 0.05), whereas rats of the obese control group had lower concentrations of total carnitine in plasma and skeletal muscle than lean rats (P < 0.05).Conclusion: The results show for the first time that niacin administration stimulates the expression of genes involved in carnitine uptake and biosynthesis and improves the diminished carnitine status of obese Zucker rats. We assume that the induction of genes involved in carnitine uptake and biosynthesis by niacin administration is mediated by PPAR-activation.

Harvard Citation style: Couturier, A., Ringseis, R., Most, E. and Eder, K. (2014) Pharmacological doses of niacin stimulate the expression of genes involved in carnitine uptake and biosynthesis and improve the carnitine status of obese Zucker rats, BMC Pharmacology and Toxicology, 15, Article 37. https://doi.org/10.1186/2050-6511-15-37

APA Citation style: Couturier, A., Ringseis, R., Most, E., & Eder, K. (2014). Pharmacological doses of niacin stimulate the expression of genes involved in carnitine uptake and biosynthesis and improve the carnitine status of obese Zucker rats. BMC Pharmacology and Toxicology. 15, Article 37. https://doi.org/10.1186/2050-6511-15-37