The tissue kinetics of key metabolites of ischaemic and postischaemic tissue damage were studied in the intercellular space of human skeletal muscle by microdialysis. In vivo microdialysis calibration experiments (n = 5) yielded the basal intercellular concentration of glucose in human skeletal muscle (3.6 +/- 0.6 mM; mean +/- SD). The corresponding mean plasma glucose concentration was 4.3 +/- 0.2 mM which was significantly higher. The time vs. concentration profiles of intercellular glucose (n = 7), lactate (n = 5), TxB2 (n = 6) and urea (n = 8) were characterized during a 20 min period of leg constriction. TxB2 increased exclusively during reperfusion in comparison to baseline (n = 6). Administration of 500 mg acetylsalicylic acid, 5-10 min after onset of ischaemia blunted TxB2-response to reperfusion (n = 4). It is concluded that intercellular muscle glucose concentration is less than that in plasma. Glucose uptake in skeletal muscle is rapid even under ischaemic conditions. Synthesis and release of TxB2 is not evident during ischaemia. TxB2 mediated reperfusion injury might be reduced by acetylsalicylic acid, even if administered after onset of ischaemia.