[Zinc in the human prostate]

The quantities of zinc naturally present in prostatic epithelial cells determine the human prostate to be a zinc-rich gland. Since the growth of the prostate depends on androgenic steroid hormones, interrelationships between steroids and zinc were investigated. It appears now that zinc in hyperplastic prostates is bound to cytoplasmic citrate. Metabolic homeostasia in prostatic secretory cells may be insured by inhibition of cis-aconitase by free zinc and its binding to accumulating citrate. The yields of bound zinc are decreased by androgenic steroids (testosterone, 5 alpha-dihydrotestosterone, 5 alpha-androstane-3 alpha, 17 beta-diol) which increase in turn the levels of free zinc, the uptake and the reduction of testosterone and citrate accumulation. In dedifferentiated hormono-independent neoplastic cells, there is less reduction of testosterone and a drastic decrease in zinc levels due to the sole presence of a metallothionein for binding.