|Title:||Description of a new anabolic steroid binding site on hepatic microsomes of rat||Authors:||Boada, L. D.
Luzardo, O. P.
Diaz-Chico, B. N.
|Issue Date:||1996||Publisher:||0212-7113||Journal:||Revista de Toxicologia||Abstract:||It has been described that anabolic-androgenic steroids interact in the liver with the Androgen Receptor and with the Glucocorticoids Receptor. However hepatic microsomes also have another steroid binding site, capable of binding glucocorticoids, progestagens and synthetic estrogens. The interaction of 17α-Alkyl steroids with the Androgen or Glucocorticoids Receptors has been widely studied, however little is known about their interaction with liver microsomes. The microsomal steroid binding site was measured by a radioligand binding assay with [3H]dexamethasone or [3H]stanozolol. The microsomal steroid binding site show low affinity for natural androgens or methyltrienolone; however it was capable of interacting with some 17α-alkyl androgens, specially with stanozolol and danazol. The Scatchard analysis of the binding of [3H]dexamethasone to liver microsomes in the presence of increasing concentrations of stanozolol revealed a decrease in both, the affinity and the B(max), compatible with a non-competitive inhibition. Stanozolol provoked an irreversible inhibition of the binding activity when microsomes were preincubated with this anabolic-androgenic steroid. The use of [3H]stanozolol allowed us to detect a microsomal binding site, highly specific for stanozolol and danazol. The Scatchard analysis of the binding of [3H]stanozolol to liver microsomes showed a downward curvature, compatible with a positive cooperative pattern. 1. Liver microsomes have two binding sites for steroids: one of them is capable of interacting with glucocorticoids, androgens and other steroids. The other one is highly specific for stanozolol and danazol. 2. The fact that none of these binding sites interact with natural androgens, gives rise to the possibility that the hepatotoxic effects described for stanozolol could be mediated through its interaction with these microsomal binding sites.||URI:||http://hdl.handle.net/10553/47333||ISSN:||0212-7113||Source:||Revista de Toxicologia[ISSN 0212-7113],v. 13, p. 26-31|
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