Changes in serum and tissue zinc levels in sex hormone-induced prostatic carcinogenesis in the Noble rat

We investigated the changes in serum and tissue zinc levels in the Noble ra t prostate gland under different pathological conditions induced by the adm inistration of a combination of testosterone and 17 beta-estradiol. The res ults showed that there were significant differences in serum zinc values be tween normal and hormone-treated rats with prostatic hyperplasia, dysplasia and prostatic carcinoma (p < 0.05), although there was no significant diff erence among rats with different forms of prostatic lesions (i.e. hyperplas ia, dysplasia and prostatic adenocarcinoma). There was also a difference in zinc content between the lateral prostate (LP), ventral prostate (VP) and dorsal prostate (DP) in normal rats. The zinc levels of LP were several tim es greater than those of either VP or DP (p < 0.01). There was also a great difference in zinc levels between the normal and the hyperplastic/dysplast ic and carcinomatous LP and VP (p < 0.05). The levels of zinc in both LP an d VP were increased in hyperplasia/dysplasia and carcinoma. On the other ha nd, the zinc levels of LP were much higher than those of VP in hyperplasia/ dysplasia and carcinoma (p < 0.01), which may be correlated with the incide nce of prostate cancers in these lobes (i.e, higher in LP and much lower in VP). In contrast, in DP, the levels of zinc were not affected, which may b e correlated with the very low incidence of carcinoma in this lobe. Our dat a suggest that the difference in zinc levels among these lobes reflect the heterogeneity in zinc content in various lobes of the rat prostate. The gro wth and development of prostatic lesions in LP and VP may be positively cor related with the significant increase in tissue zinc levels in these lobes. On the other hand, the lack of response of DP to carcinogenesis may be due to its relatively stable low zinc levels. It is suggested that tissue zinc content may be used as a marker for prostatic lesions, including hyperplas ia, dysplasia and carcinoma, while serum zinc levels may be a useful indica tor for abnormal prostatic growth. Copyright (C) 2000 S. Karger AG, Basel.