Fatty acids as regulators of lipid metabolism

Structurally defined fatty acid species, which are the straight-chain monou nsaturated and polyunsaturated and the branched-chain building blocks of di etary fats and oils, have the potential to regulate lipid metabolism. Focus sing on the situation in rodents and in man we describe first the non-enzym ic proteins that confer regulatory properties to fatty acids. These are the ligand activated receptors in the nuclei (peroxisome proliferator activate d receptors, hepatic nuclear factor 4, liver-X-receptor), sterol regulatory element binding proteins and the soluble and membrane-bound transport prot eins for fatty acids and derivatives (fatty acid binding proteins, acyl-CoA binding protein, fatty acid translocator, fatty acid translocator proteins ). Then we follow the path of the dietary fatty acids from digestion to the ir ultimate fate in the cell and critically address their regulatory roles. Fatty acids and/or derivatives interact either directly with enzymes to af fect activity, or with the nuclear transcription factors, or affect the sta bility of mRNAs encoding proteins involved in lipid metabolism. Knowledge o f the effects of fatty acid species on the genetic machinery as a whole cou ld become a starting point for individualization of nutritional needs.