Alteration of Cholesterol Metabolism Induced by Anabolic Steroid, Oxandrolone, Administration to Rats

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Remarkable lowering of plasma cholesterol by oxandrolone administration was observed in the hypercholesteremic rats fed the high cholesterol diet but not in the rats fed the low cholesterol diet during the short experimental period. Tween 80 induced hypercholesteremia or diabetic hypercholesteremia was not prevented by oxandrolone.
Although the bile amount of the rats with bile fistulae was not influenced by the hormone administration, the biliary excretion of cholic acid and cholesterol was increased in the hormone treated group. Excretion of the radioactivity into the bile after labeled cholesterol injection was accelerated by oxandrolone. When 26-¹⁴C cholestereol was injected into the animals, more radioactivity was found in expiratory CO₂ of the oxandrolone treated rats than that of the controls. Influx of administered cholesterol from plasma to the liver was accelerated in the oxandrolone fed rats with bile duct obstruction, and outflux of endogenous cholesterol from the liver to plasma was also increased.
Cholesterol was accumulated in the liver by oxandrolone treatment when cholesterol was given simultaneously with the hormone, but the decrease of the hepatic cholesterol contents after the interruption of cholesterol feeding was promoted by the hormone administration.
Therefore, the main mechanism of the hypocholesteremic effect of anabolicsteroids is assumed to be both the acceleration of the shift of cholesterol from plasma to liver and secondary stimulation of cholesterol catabolism to bile acid.