The major androgen-dependent disorder in the elderly is benign prostatic hyperplasia. In the fifth decade of life, the prostate resumes growth in most men, commencing in the periurethral region with proliferation of glandular and stromal elements. This growth spurt requires a functioning testis and is thought to be mediated by dihydrotestosterone that is synthesised within the gland. Inhibition of dihydrotestosterone formation in animals causes involution of the prostate, despite an elevated concentration of testosterone in the tissue. Furthermore, in elderly men, prostate dihydrotestosterone content remains high.
