Effects of 4-tert-octylphenol given in drinking water for 4 months on the male reproductive system of Fischer 344 rats.

The environmental pollutant 4-tert-octylphenol (OP) is both toxic and estrogenic to mammalian cells, and injection of OP into adult male rats has devastating effects on their reproductive system. We now report the effects of OP in drinking water ( 1 x 10(-5), 1 x 10(-7) or 1 x 10 (-9) M) on the male reproductive system. Exposure of adult male rats for 4 months to any tested dose of OP had no significant effect on water or food consumption; body weight gain; hematocrit; reproductive organ weights; mean serum LH, FSH or testosterone concentrations; germ cell yield or relative numbers of different classes of testicular cells; or testicular sperm number. In contrast, all doses of OP caused an increase in epididymal sperm with tail abnormalities that would interfere with sperm motility, and the highest dose decreased epididymal sperm number. Our findings raise the possibility that consumption of OP in drinking water may adversely influence male reproductive fertility.