Abstract
A diet enriched with citrulline (CIT) reduces white adipose tissue (WAT) mass. We recently showed that CIT stimulated β-oxidation in rat WAT explants from young (2–4 months) but not old (25 months) rats. Here we show that both in old rats and high-fat-diet-fed young rats, uncoupling protein one (UCP1) mRNA and protein expressions were weaker than those in young control rats. Selectively in WAT from young rats, a 24h CIT treatment up-regulated expressions of UCP1, peroxisome proliferator-activated receptor-α (PPARα), PPARγ-coactivator-1-α and mitochondrial-transcription-factor-A whereas it down-regulated PPARγ2 gene expression, whatever the diet. These results suggest that CIT induces a new metabolic status in WAT, with increased β-oxidation and uncoupling of respiratory chain, resulting in energy expenditure that favors fat mass reduction.
Abbreviations:
- ARG, arginine
- ASL, argininosuccinate lyase
- ASS, argininosuccinate synthase
- BSA, bovine serum albumin
- CD, control diet
- CIT, citrulline
- CPT1-b, carnitine palmitoyl transferase 1-b
- EPI, epididymal
- HFD, high-fat-diet
- KREBS, Krebs Ringer Buffer Saline
- NEFA, non-esterified fatty acids
- NO, nitric oxide
- NOS, nitric oxide synthase
- PEPCK-C, cytosolic phosphoenolpyruvate carboxykinase
- PGC-1α, peroxisome proliferator-activated receptor gamma co-activator 1α
- PKA, protein kinase A
- PPAR, peroxisome proliferator-activated receptor
- RET, retroperitoneal
- TFAM, mitochondrial transcription factor A
- VLCAD, very long chain acyl-CoA dehydrogenase
- WAT, white adipose tissue
Disclosure of Potential Conflicts of Interest
No potential conflicts of interest were disclosed.
Acknowledgment
We thank Dr. Brigitte Potier for providing us with a series of old rats.
Funding
We acknowledge the Institut National de la Santé et de la Recherche Médicale and the Université Paris Descartes for their financial support.