OBJECTIVETo investigate the possible effects of oral cadmium(Cd) exposure on the expression levels of metallothionein-I and metallothionein-II (MT-I and MT-II) mRNA and the distribution of zinc (Zn) and Cd in rat prostate.

METHODSCadmium was given to rats at doses of 50, 100, and 200 mg/kg in drinking water. The contents of Zn and Cd in prostate were measured by atomic absorption spectrometry(AAS), and the levels of MTs mRNA were determined by RT-PCR.

RESULTSAfter Cd administration, the content of Zn was decreased in both the ventral and the dorsolateral lobes of rat prostate. In 200 mg/kg Cd group, the contents of Zn in ventral prostate were 9.5 and 8.5 micrograms/g wet weight respectively after one month and six months, which were significantly lower than those of control(17.0 and 18.9 micrograms/g wet weight). In contrast, the contents of Cd in both ventral and dorsolateral lobes of prostate significantly increased with the increasing dose and time of Cd administration. It was also noted that Cd administration resulted in a significant down-regulation of the expression of MT-I and MT-II mRNA in rat ventral prostate. In 200 mg/kg Cd group after one and six months, the relative expression levels of MT-I (0.410, 0.339 respectively) and MT-II (0.100, 0.112 respectively) were significantly lower than those of MT-I (0.760, 0.830 respectively) and MT-II (0.429, 0.439 respectively) in control group.

CONCLUSIONOral Cd exposure could influence the distribution of Zn and the expression levels of MTs mRNA in rat prostate.