Site differences in human subcutaneous adipose tissue metabolism in obesity.

The results of several recent studies indicate that there are regional differences in the metabolism of subcutaneous fatty depots in obesity. Fat cells are larger in the femoral than in the abdominal region. Lipids are mobilized at a slower rate but synthesized at a higher rate in the former than the latter region. Fasting is accompanied by an increased rate of fat mobilization and a decreased rate of fat synthesis in all fat depots. These changes are, however, more pronounced in abdominal than in femoral fat. There are also regional differences in the hormonal regulation of fat metabolism in obesity. The action of insulin is most pronounced in the femoral region whereas that of catecholamines is most marked in the abdominal area. The regional differences in hormone action are further enhanced during therapeutic fasting. These differences may partly explain why adiposity is more catching in some fatty regions than in others and also why some obese areas are resistant to slimming.