Influence of blood flow on fatty acid mobilization form lipolytically active adipose tissue

Subcutaneous, ingvinal adipose tissue from dogs was perfused with blood to which had been added isoprenaline and theophyllamine in order to stimulate lipolysis. The supply of free fatty acid (FFA) carrier to the tissue was varied either by variations in the rate of blood flow or by changes in the albumin concentration of the perfusing blood at constant flow rate. The net production of FFA from the tissue was found to depend on the supply of carrier over a range from 0.1 -- 12 mumoles of albumin x 100 g tissue-1 x min-1. The corresponding molar FFA/albumin ratios in adipose venous blood varied between 12.1 and 1.2. The changes in FFA production appeared to be due to varying degrees of reesterification rather than changes in the rate of lipolysis. The findings suggest that the increase in adipose tissue blood flow demonstrated during various lipolytic conditions is of physiological importance by facilitating the removal of FFA from adipose tissue. Equilibration experiments showed the FFA binding capacity of both dog serum and human plasma to be above than calculated from the association constants of purified human albumin, suggesting the binding of FFA to other plasma carriers than albumin.