FATTY-ACIDS, ADIPOCYTIC METABOLISM AND THE DEVELOPMENT OF ADIPOSE-TISSUE

Obesity corresponds to an hypertrophy of white adipose tissue. This ti ssue is the main energy store of the organism, and is specialized in t he storage and release of fatty acids. Adipose fatty acids originate e ndogenously (de novo lipogenesis) or exogenously (diet). Thus, the fat ty acid composition of adipose tissue reflects the quality of dietary fatty acids, which is usefull in epidemiological studies. However, a g ood knowledge of fatty acid metabolism in adipocytes is a pre-requisit e. It has been shown that the storage of individual dietary fatty acid s in adipose tissue is selective and that this selectivity is partly r elated to that of their mobilization. Fatty acid mobilization from fat cells depends on their molecular structure, increasing with unsaturat ion and decreasing with chain length. The quantity but also the qualit y of dietary fatty acids affect the development of adi pose depots. Po lyunsaturated fatty acids limit the hypertrophy of adipose tissue in c ontrast to saturated and unsaturated fatty acids. Polyunsaturated fatt y acids act within the adipocyte (stimulation of lipolysis, reduction of lipogenesis), but also in the whole body where they stimulate the p artitioning of ingested energy towards utilization at the expense of s torage. Thus, the nature as well as the quantity of ingested fatty aci ds should be taken into account to fully understand the relationships between dietary fatty acids and obesity.