Isolation and characterization of androgen receptors from male target cells

Androgens exert their action after binding to cytoplasmic receptors resulting in the formation of androgenreceptor complexes. This initial event is followed by activation, translocation to the nucleus and interaction with chromatin acceptor sites of the androgen-receptor comulexes. Bound to chromatin, the androgen-receptor complex stimulates many biochemical events resulting in gene expression and starting with RNA-synthesis. Further detailed understanding of the complex processes requires a purified receptor preparation. Due to the low amount of receptors present ln androgen target organs, large scale isolation of these receptors requires a suitable source. Thusfar it seems that androgen receptors from different sources have similar characteristics. In this respect seminal vesicles of the ram contain an androgen receptor comparable to the receptor present in rat prostate (chapter 4.3 and appendix paper II). Studies were performed to purify the receptor present ln ram seminal vesicles, and an almost two thousand fold purified receptor preparation has been obtained (chapter 4.4 and appendix paper III). Nuclear localization and acceptor sites of androgen-receptor complexes on the chromatin in target cells have hardly been studied. To gain more insight in the mechanism of interaction of androgen-receptor complexes with chromatin acceptor sites, the usefulness of purified androgen receptors was investigated. In preliminary studies high affinity interaction of androgen-receptor complexes with isolated chromatin was observed (chapter 5) and the possibilities for further investigation are discussed (chapters 6.3 and 6.4).