PPARalpha-dependent induction of the energy homeostasis-regulating nuclear receptor NR1i3 (CAR) in rat hepatocytes: potential role in starvation adaptation.

Universität Potsdam, Institut für Ernährungswissenschaft, Biochemie der Ernährung, Arthur-Scheunert-Allee 114-116, D-14558, Nuthetal, Germany.
FEBS Letters (Impact Factor: 3.34). 01/2008; 581(29):5617-26. DOI: 10.1016/j.febslet.2007.11.011
Source: PubMed

ABSTRACT A tight hormonal control of energy homeostasis is of pivotal relevance for animals. Recent evidence suggests an involvement of the nuclear receptor NR1i3 (CAR). Fasting induces CAR by largely unknown mechanisms and CAR-deficient mice are defective in fasting adaptation. In rat hepatocytes CAR was induced by WY14643, a PPARalpha-agonist. A DR1 motif in the CAR promoter was necessary and sufficient for this control. The PPARalpha-dependent increase in CAR potentiated the phenobarbital-induced transcription of the prototypical CAR-dependent gene CYP2B1. Since free fatty acids are natural ligands for PPARalpha, a fasting-induced increase in free fatty acids might induce CAR. In accordance with this hypothesis, CAR induction by fasting was abrogated in PPARalpha-deficient mice.

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