MICRODIALYSIS MEASUREMENTS IN SKIN - EVIDENCE FOR SIGNIFICANT LACTATERELEASE IN HEALTHY HUMANS

To assess net lactate release from dermal skin, seven lean, healthy me n were studied after overnight fasting. Two microdialysis catheters we re inserted in the upper dermal tissue, as ensured by ultrasound scann ing, in the periumbilical area. Each catheter was calibrated in situ t o get an estimate of the lactate concentration in interstitial fluid ( 1,001 +/- 24 mu mol/l), which in turn enabled calculation of the local capillary-venous lactate concentration (963 +/- 25 pmol/l). Concomita ntly, arterialized venous plasma lactate (673 +/- 32 mu mol/l), blood hematocrit (43 +/- 1%), and skin blood flow (3.8 +/- 0.9 ml . 100 g(-1 ). min(-1)) as measured by Xe-133 clearance were determined, and derma l apparent lactate release (570 +/- 89 nmol . 100 g(-1). min(-1)) was estimated according to the Fick principle. During an oral glucose tole rance test (OGTT, 75 g), the dermal interstitial-arterial lactate diff erence decreased significantly to reach a nadir at 60 min. Moreover, n o significant increase in shin blood flow was seen during the OGTT. In conclusion, we found a significant net lactate release from abdominal dermal skin after overnight fasting, whereas no significant increase was observed during an OGTT.