Interaction of spironolactone with rat skin androgen receptor

The study investigated the characteristics of the androgen receptor (AR) in the dorsal skin of male rats, finding that it shares similarities with the AR in rat prostate in terms of affinity constant, binding specificity, and sedimentation profile. The research showed that the skin AR is largely occupied by endogenous hormones from gonadal or adrenal sources. The study also demonstrated that administering spironolactone or its active metabolite canrenone to castrated rats led to a significant reduction in available AR binding sites due to competitive inhibition. The findings suggest that spironolactone's antiandrogenic effects on the skin are likely due to canrenone's inhibition of the formation of specific testosterone or 5 alpha-dihydrotestosterone receptor complexes in the cytoplasm and nuclei.