Effect of denervation or castration on steroid receptors in rat bulbocavernosus/levator ani muscles

Alterations in cytosolic glucocorticoid (GR) and androgen receptors (AR) in atrophic rat bulbocavernosus/levator ani muscles (BCLA) were investigated. The BCLA was removed 15 days after denervation (DEN) of the right part of BCLA or castration (CAS) and compared with the innervated left part of BCLA (INN) or the BCLA from sham-operated rats (SHAM). Receptor analyses were performed using charcoal adsorption or agar-gel electrophoresis. The main results were: (1) no alterations in KD were observed; (2) GR were increased in DEN compared to INN when expressed per mg cytosolic protein (P less than 0.0001) or g tissue (P less than 0.0002) as well as in DEN compared to SHAM when expressed per mg protein (P less than 0.0002) or g tissue (P less than 0.0003); (3) GR were increased in CAS compared to SHAM when calculated per mg protein (P less than 0.05) or g tissue (P less than 0.04); (4) no differences between DEN and INN or SHAM were noted when results were expressed per mg DNA; (5) AR were increased in CAS compared to SHAM only when expressed per mg protein (P less than 0.003); (6) GR/AR was increased in DEN compared to INN (P less than 0.0001) or SHAM (P less than 0.0006), but unaltered in CAS compared to SHAM. The data reflect differences in the behaviour of GR and AR in the atrophic BCLA and suggest a relative increase in sensitivity to glucocorticoids compared to androgens in the DEN muscle.