Effects of stanozolol and L-carnitine on erythrocyte osmotic fragility during aerobic exercise in rats

The effect on erythrocyte osmotic fragility of two anabolic agents, widely used to improve physical performance, has been studied. These agents, the steroid derivative, stanozolol, and a quaternary amine,l-carnitine, were administered to rats at rest and while performing running exercises, for 12 weeks. The results show that exercise does not alter the haemolysis curve. Administration of both agents in resting condition does increase the osmotic resistance of the erythrocytes. The combined effect of drug administration and physical exercise further increases the osmotic resistance in the case of stanozolol, presumably due to the steroid-erythrocyte membrane interaction as well as by an erthyropoietic effect.