In prostatic cytosol DHT1 is metabolized to 5α-androstane-3α (or β), 17α-diols with a half life of 2 h even at 4°C. Thus, [3H]DHT appears to be a poor marker for a quantitative assessment of androgen receptors (AR). Methyltrienolone (R1881) seems to be advantageous as it is not metabolized. However, because of considerable binding to progestin receptors, assays using [3H]R1881 are not specific for AR in tissues containing progestin receptors. We, therefore, developed a specific assay for AR using [3H]DHT (14 nm) as marker, where metabolism of DHT is prevented by pre-incubation with NAD+-nucleosidase.
The [3H]DHT-receptor complex is separated from free, SHBG-bound and unspecifically bound [3H]DHT by agar gel electrophoresis. The binding sites of high affinity and low capacity are characterized by suppression with unlabelled R1881 (2 μm) in a parallel assay. Under these conditions DHT and R1881 appear to have the same kinetics of association and dissociation.
Weighted non-linear regression analysis of specific binding capacity at various ligand concentrations reveals that in rat prostatic cytosol the affinity of DHT (Kd = 0.405 ± 0.0839 nm) is significantly higher (P < 0.01) than that of R1881 (Kd = 1.25 ± 0.271 nm).
EJE is committed to supporting researchers in demonstrating the impact of their articles published in the journal.
The two types of article metrics we measure are (i) more traditional full-text views and pdf downloads, and (ii) Altmetric data, which shows the wider impact of articles in a range of non-traditional sources, such as social media.
More information is on the Reasons to publish page.
Sept 2018 onwards | Past Year | Past 30 Days | |
---|---|---|---|
Full Text Views | 2 | 2 | 0 |
PDF Downloads | 1 | 1 | 0 |