Tissue content of adenosine,inosine and hypoxanthine in the rat kidney after ischemia and postischemic recirculation

Summary The effect of renal ischemia of 15 s to 60 min duration on the tissue levels of adenosine, inosine and hypoxanthine was investigated in Sprague Dawley rats. A sharp increase in the tissue levels of adenosine from 5.13±0.56 to 31.3±2.96 nmol/g wet weight after 1 min of ischemia was found. The tissue levels of inosine and hypoxanthine in the controls were 3.62±0.51 and 3.19±0.76 nmol/g wet weight, respectively. Maximal levels of adenosine (38.1±6.3 nmol/g wet weight) were reached after 10 min of ischemia. The hypoxanthine levels rose steadily up to 922±183 nmol/g wet weight after 60 min of ischemia. Recirculation of 15 min after 60 min ischemia resulted in a fall of adenosine and inosine levels to values comparable to controls, whereas hypoxanthine was elevated above control values. In a second experimental series with tracing of renal blood flow (RBF) by a means of an electromagnetic flow meter a transient marked reduction of RBF after occlusion of the renal artery for 30 s was observed. The 3-fold increase of adenosine tissue levels within 30 s of renal artery occlusion and the inhibition of the postocclusive RBF reduction by theophylline (3.3 mol/100 g body weight) make it likely that this phenomenon may be caused by intrarenal adenosine.Parts of this investigation were presented at the 46th Meeting of the German Physiological Society in Regensburg, March 15–20, 1976.Supported by the Deutsche Forschungsgemeinschaft Os 42/2