Absolute Lactate Concentration in Subcutaneous Adipose Tissue Measured by Open Flow Microperfusion

The aim of tbis study was the measurement of the absolute subcutaoeous lactate concentration in the interstitial fluid of subcutaneous adipose tissue using open flow microperfusion and a established calibration protocol (no net flux protocol). Using open flow microperfusion a perforated double lumen catheter was set into the subcutaneous adipose tissue and was perfused with an isotonic ionfree perfusate. Due to the perforations of the catheter the perfusate partially equilibrated with the surrounding tissue fluid. We estimated the absolute lactate concentration of the subcutaneous adipose tissue in six healthy volunteers. The lactate concentration estimated for the point of no net exchange was 136 mmol 1 (r = 0.98, n = 6). The arterialized plasma lactate concentration was significantly Iower (0.61 ± 0.03 mmol l", mean ± SEM; n 6; p < 0.05) compared with the estimated subcutaneous lactate concentration. As demonstrated by the microdialysis technique and the measurement of arterio venous differences the present data confirm that subcutaneous adipose tissue is a significant source of lactate production du ring basal conditions after