Reduced high affinity 5 -dihydrotestosterone receptor capacity in the ventral prostate of the aging rat

Cytoplasmic extracts of ventral prostates obtained from young (50–90 day old) rats 24 hours post orchidectomy contained high affinity binding activity for 5α-dihydrotestosterone which migrated with a sedimentation coefficient of 10–11S on linear sucrose gradients. By contrast, when cytoplasmic extracts were prepared from ventral prostates of aging rats (10–14 months old), 80 percent of the animals evidenced a complete absence of 10–11S binding activity. A single extract prepared from the ventral prostates of the remaining aging animals in the 10–14 month age category had a level of 10–11S binding activity that was about 20 to 25 percent of the value routinely obtained for identical preparations from young animals. Cytoplasmic extracts prepared from the ventral prostate of animals older than 14 months were always found to be devoid of 10–11S binding activity.