EFFECTS OF GEMFIBROZIL ON THE OXYGEN-TRANSPORT PROPERTIES OF ERYTHROCYTES

1 In the present study we have investigated the effects of the relatively low plasma concentrations of gemfibrozil (GFZ) found in clinical practice on the oxygen dissociation curve (ODC) of erythrocytes. 2 ODCs were measured at 30 degrees C and 37 degrees C and at pH 7.4: a) both on HbA solution and erythrocytes incubated in vitro with gemfibrozil and clofibric acid; b) on erythrocytes from healthy volunteers treated with a single oral dose of gemfibrozil. 3 These experiments showed a significant drug-induced shift of the ODC towards lower O-2, affinity values without any significant modification of metabolic parameters of erythrocytes such as intracellular pH and intraerythrocytic levels of ATP and DPG. 4 In our experimental conditions gemfibrozil appears to lower both in vitro and in vivo, the partial pressure of oxygen required to give 50% of the haemes saturated with oxygen (P-50) Of erythrocytes from the control value of 24 +/- 0.5 mm Hg to 29 +/- 0.5 mm Hg (mean +/- s.d.; P < 0.02 by ANOVA). 5 These data clearly indicate that therapeutic doses of gemfibrozil may influence the oxygen transport properties of red cells. This effect could have relevant pharmacological and toxicological implications.