Steroid-binding properties of the rat seminal vesicle androgen receptor: short-term and long-term competition of various steroids with radioactive dihydrotestosterone.
Competition of 22 steroids with [3H]-dihydrotestosterone for the binding to the androgen receptor of the rat seminal vesicle has been studied. The effect of each competitor was determined in short term (1 h) and long term (67 h) incubations, and the results were evaluated by considering the kinetic aspects of competition. This approach made possible to investigate separately the ligand specificity of the association and dissociation parts of the steroid-receptor interaction. According to competitory behavior, the investigated steroids could be divided into three groups. In Group I, the association and dissociation rates of the competitors are close to that of 5 alpha-dihydrotestosterone. Steroids in Group II can still associate at a remarkable rate with the receptor, but the resulting complexes are much less stable than the 5 alpha-dihydrotestosterone-receptor complex. Finally, steroids of Group III do not exhibit significant binding. By correlating the binding characteristics and the structure of the test compounds it was possible to assess the significance of certain features of steroid molecules in the binding. Moreover, other correlations between the competitive behavior and some known biological activities of these steroids point to the potential usefulness of our procedure in the screening of synthetic steroids.
D000818:Animals; D001667:Binding, Competitive; D013196:Dihydrotestosterone / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D051381:Rats; D011944:Receptors, Androgen / Q000378:metabolism*; D011987:Receptors, Steroid / Q000378:metabolism*; D012669:Seminal Vesicles / Q000378:metabolism*; D013256:Steroids / Q000378:metabolism*; D013997:Time Factors
D011944:Receptors, Androgen; D011987:Receptors, Steroid; D013256:Steroids; D013196:Dihydrotestosterone