Subcutaneous adipose tissue blood flow in the abdominal and femoral regions in obese women: effect of fasting.

Subcutaneous adipose tissue blood flow (ATBF) was measured by the local clearance of 133Xe from the abdominal and femoral regions of nine individuals with non-endocrine obesity before and after seven days of fasting. Fifteen non-obese individuals served as controls. In the obese group ATBF was similar in the abdominal and femoral regions, 1.7 +/- 0.2 and 1.8 +/- 0.2 ml/min/100 g adipose tissue, respectively. In contrast, in the non-obese group the abdominal ATBF was higher, 4.1 +/- 0.6 and 2.4 +/- 0.2 ml/min/100 g adipose tissue, respectively (P < 0.01). During fasting, ATBF in the abdominal region increased by 45% (P < 0.01), but it remained unchanged in the femoral region. The mechanisms behind the differences in responses to fasting in the two regions are unsettled but may depend on regional differences in lipolytic activity and responses to vasoactive substances. Furthermore, the vasodilator response to fasting in the abdominal region in combination with the higher lipolytic rate in that region may be a pathophysiological factor behind the increased cardiovascular morbidity associated with abdominal obesity.