CLOCK and metabolic syndrome: Furthermore, homozygous Clock mutant mice have impaired feeding rhythms, become hyperphagic and obese, and develop the metabolic syndrome.53 CLOCK also plays an important role in lipid metabolism by regulating the transcription of peroxisome proliferator-activated receptor α (PPARα) in mice.54 PPARα is a member of the nuclear receptor super-family and is involved in the activation of numerous pathways of lipid metabolism, including fatty acid uptake, beta-oxidation, transport into peroxisomes and omega-oxidation of unsaturated fatty acids.55