[Partial identification and variations of the cytoplasmic androgen receptor in the rat kidney]

In the course of our studies on the fate of cytoplasmic receptors for androgens in various target organs, such a receptor has been partially characterized in rat kidney cytosol: the high affinity constant, the specificity for testosterone and the formation of a hormone-receptor complex with a 8-10S sedimentation coefficient on sucrose density gradient led us to estimate that this macromolecule was similar to the rat prostate androgen receptor. This receptor is partially occupied by circulating androgens because the number of binding sites increases following castration or hypophysectomy. Constant levels of receptors have been recorded for several months in absence of testosterone. The age and the sex of animals, as well as the functional state of thyroid gland, did not affect the number of binding sites. These receptor characteristics may explain the slight renotrophic action of androgens in rat kidney.