CO-PARTICIPATION OF THROMBOXANE-A2 AND LEUKOTRIENE-C4 AND LEUKOTRIENE-D4 IN MEDIATING CYCLOSPORINE-INDUCED ACUTE-RENAL-FAILURE

The relative role of thromboxane (TxA2) and sulfido-peptide leukotrienes C4 (LTC4) and D4 (LTD4) in the acute renal failure induced by cyclosporine was studied in the rats. Bolus i.v. administration of 20 mg/kg of CsA but not vehicle to adult male Sprague-Dawley rats resulted in a significant fall in glomerular filtration rate from 0.85 +/- 0. 10 and renal plasma flow (RPF) 2.45 +/- 0.14 ml/min/100 g body wt to values at 20 min of 0.47 +/- 0.03 and 1.01 +/- 0. 12 ml/min/100 g body wt (P < 0.01), respectively, without a fall in mean arterial pressure. This hemodynamic effect was maintained for the following 40-min period. Pretreatment of rats with the TxA2 receptor antagonist GR32191 (3 mg/kg i.v.) allowed a partial but significant preservation of GFR (0.60 +/- 0.05 ml/min/100 g body wt) and RPF (1.55 +/- 0.12 ml/min/100 g body wt). In addition, the antagonism of endogenously produced LTC4 and LTD4 with the putative receptor antagonist L-649,923 (1 mg/kg i.v.) partially prevented the fall in GFR (0.65 +/- 0.07 ml/min/100 g body wt) and RPF (1.80 +/- 0.18 ml/min/100 g body wt) at 20 min after CsA injection. The combined administration of GR32191 and L-649,923 completely abolished the CsA-induced decline in GFR (0.80 +/- 0.09 ml/min/100 g body wt) and RPF (2.40 +/- 0.12 ml/min/100 g body wt). These findings suggest that TxA2 and LTC4/LTD4 participate in mediating renal function deterioration induced by acute CsA administration in the rat.