EXPRESSION AND DEGRADATION OF RAT ANDROGEN RECEPTOR FOLLOWING CASTRATION, TESTOSTERONE REPLACEMENT AND ANTIANDROGENS ADMINISTRATION - ANALYSIS BY WESTERN-BLOT AND IMMUNOHISTOCHEMISTRY

To elucidate the autoregulation of androgen receptor (AR) by androgen and antiandrogen, Western blot analysis and immuno-histochemical study were performed. Castration reduced the immunodetected AR content, and nuclear staining was lost without cytoplasmic staining. Testosterone (T) supplement restored AR content. Quick response of AR content resto ring following single administration of T was observed 48 hours after castration. The recovery of AR content detected by Western blot under each condition was accompanied by recovery of the reduced unclear stai ning intensities in the epithelia. Neither steroidal nor non-steroidal antiandrogens, cholormadinone acetate and flutamide, altered the AR c ontent in normal rat ventral prostate 5, 12, 24 or 48 hours after sing le administration. Furthermore, neither of the drugs at various doses altered AR levels 12 hours after single administration. In summary, th e rat AR is upregulated by androgen. Single administration of antiandr ogens have no effect on immunodetected AR content. (C) Tohoku Universi ty Medical Press.