Title: Evidence for androgen and estrogen receptors in castrated ram pituitary cytosol: Influence of time after castration
Abstract: A comparison of testosterone, 5α-dihydrotestosterone and 17β-estradiol binding to cytosol fractions of ram anterior pituitary was conducted in animals 24 h or 2 years after castration. The three [3H]-steroids were bound to macromolecules which sedimented on a sucrose density gradient at approx. 7S. Polyacrylamide gel electrophoresis and competitive binding assays with cyproterone acetate and diethylstilbestrol indicated the presence of steroid receptors as distinct from non-specific binding proteins or specific plasma proteins. Affinities of testosterone and 5α-dihydrotestosterone for cytosol macromolecules by competitive binding assays suggested the presence of androgen receptors which are clearly different from the estrogen receptor. The affinity constants for the testosterone, 5α-dihydrotestosterone and estradiol binding reactions were 3.70 × 109 M−1, 1.47 × 1010 M−1 and 3.41 × 109 M−1 respectively in the 24 h castrated rams. These values tended to decrease for testosterone, increase for 5α-dihydrotestosterone and to remain steady for estradiol 2 years after castration. Numbers of sites were 11.75, 15.6 and 181 × 10−15 mol/mg protein for testosterone, 5α-dihydrotestosterone and estradiol respectively 24 h after castration. Number of sites decreased by 43% for testosterone and 60% for 5α-dihydrotestosterone 2 years after castration but the loss of receptor sites was 59% and 71% when the results were expressed per mg of DNA. Number of sites for estradiol did not vary after castration.
Publication Year: 1979
Publication Date: 1979-06-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
Access and Citation
Cited By Count: 37
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