Aging represents a major risk factor for
prostate cancer; however, mechanisms responsible for this relationship remain unclear. Preclinical and some clinical investigations support the protective role of
selenium against
prostate cancer possibly through the reduction of oxidative stress. While increased levels of oxidative stress together with decreases in
selenium and the major cellular
antioxidant glutathione (GSH) are common in tissues of old animals, there is little data available on these parameters in the prostate. In the present study we have compared the levels of
selenium, GSH and
protein-bound GSH (GSSP) in blood and prostate tissues in young (4-month), mature (12-month), old (18 month), and very old (24 month) male F344 rats. Each prostate lobe (dorsolateral, DL; anterior, AL; ventral, VL) was analyzed separately based upon their differing potential for
prostate cancer development. At all ages,
selenium levels were lowest in DL<VL<AL. After 12 mo, an 85% reduction in
selenium in the DL was observed (P<0.05), while levels in other lobes were unchanged. In animals of all ages, levels of GSH were lowest in the VL<DL=AL and no significant changes were observed in GSH levels by 18 mo. However, GSSP, a marker of oxidative stress, was increased 90% after 18 mo in the DL only (P<0.01). These findings of age-related changes in GSSP and
selenium in the DL prostate are consistent with the sensitivity of this lobe to
carcinogenesis and, thus, may be playing a mechanistic role.