Bisphenol-A affects spermatogenesis in the adult rat even at a low dose

Bisphenol-A (BPA), a xenobiotic estrogenic compound widely used as a plastics monomer, has been suspected to have a so-called low dose effect on the reproductive system when administered transplacentally. In the present study, we investigated possible low-dose effects of BPA on spermatogenesis in adult rats. Male rats (13 weeks old; W13) were administrated a daily oral dose of BPA, ranging from 2 ng to 200 mg/kg, for 6 days and examined for testicular weight (TW) and daily sperm production (DSP) at W14 and W18. A BPA dose as low as 20 mug/kg tended to decrease TW and significantly reduced both DSP and the efficiency of spermatogenesis (DSP per gram testis) at W18, showing that BPA suppressed a normal increase in DSP and TW from W13 to W18. A single administration of 20 mug BPA/kg to W13 rats affected the intensity or mobility of several protein spots in the testicular cytosol fraction as shown by two-dimensional gel electrophoresis analysis. The present study showed that BPA at a low dose affects spermatogenesis in the adult rat.