AIMTo assess the effect of estradiol-17beta (E(2)) and bisphenol A (BPA) administered chronically by implanting a silicone tube throughout pregnancy and lactation on male pups' reproductive system in ICR mice.

METHODSFemale mice were implanted with a tube filled with 10 ng, 500 ng, 1 microg, or 10 microg of E(2), or 100 microg or 5 mg of BPA, before mating. The tube was kept in the mice throughout pregnancy and lactation, until the pups had weaned at 4 weeks of age. During the period, E(2) was released from the tube at 120 pg or 6, 12 or 120 ng/day, and BPA at 1.2 or 60 microg/day.

RESULTSMost of the mice given 1 microg and 10 microg of E(2) did not maintain their pregnancy. However, the other groups showed high rates of birth, more than 70%. At age of 4 weeks, the male pups were killed. Body weight and reproductive organ weights (testes, epididymides and accessory reproductive glands) in the treated groups did not differ from the control values, whereas the percentage of seminiferous tubules in the testis with mature spermatids was significantly lower in the groups given 10 ng and 500 ng of E(2) and 5 mg of BPA than that in the control.

CONCLUSIONChronic exposure to E(2) and BPA might disrupt spermatogenesis in male pups.