title: Inhibition of anterior pituitary estrogen-receptor complex formation by low-affinity interaction with 5 alpha-dihydrotestosterone.
abstract: A possible role for 5alpha-dihydrotestosterone in the anterior pituitary of the rat has been investigated by determining the  influence of this androgen upon the binding 17beta-estrasiol to its cytoplasmic receptor. Under equilibrium binding conditions, both testosterone and 5 alpha-dihydrotestosterone are very poor competitors for the estrogen binding sites, as compared to estrogenic compounds. 5alpha-Dihydrotestosterone, however, inhibits the initial rate of formation of the estradiol-receptor complex in a concentration-dependent manner. Steroidal specificity of this incubation is indicated by the failure of progesterone to elicit the same effect. The androgen inhibition appears to involve low-affinity interaction with the estrogen receptor, since no high-affinity binding of 5alpha-dihydrotestosterone could be detected. Kinetic analysis indicated that the inhibition is competitive, involving interaction at the estrogen-binding site of the receptor.
mesh_terms: D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D003600:Cytosol / Q000378:metabolism; D013196:Dihydrotestosterone / Q000378:metabolism*; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D007700:Kinetics; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D051381:Rats; D011956:Receptors, Cell Surface; D013739:Testosterone / Q000378:metabolism*; D014316:Tritium
chemical_list: D011956:Receptors, Cell Surface; D013196:Dihydrotestosterone; D014316:Tritium; D013739:Testosterone; D004958:Estradiol