Bisphenol A inhibits testicular functions and increases luteinizing hormone secretion in adult male rats

Effects of a xenobiotic estrogen, bisphenol A (BPA), on reproductive functi ons were investigated using adult male rats. BPA was dissolved into sesame oil and injected sc every day (1 mg/rat) for 14 days. Animals were killed b y decapitation after the final administration of BPA, and the trunk blood, pituitary, and testes were collected. Plasma concentrations of prolactin we re dramatically increased and pituitary contents of prolactin were slightly increased in the BPA group compared to the control group. Plasma concentra tions of testosterone were decreased and plasma concentrations of LH were i ncreased in BPA-treated rats compared to control rats. Testicular contents of inhibin were decreased in BPA-treated rats compared to control rats, alt hough plasma concentrations of inhibin were not changed after administratio n of BPA. The testicular response to hCG for progesterone and testosterone release was decreased in BPA-treated rats. Administration of BPA did not ch ange the pituitary response to luteinizing hormone-releasing hormone (LH-RH ) in castrated male rats treated with testosterone. Male sexual behavior al so was not changed as a result of BPA treatment. These results suggest that BPA directly inhibits testicular functions and the increased level of plas ma LH is probably due to a reduction in the negative feedback regulation by testosterone. The testis is probably a more sensitive site for BPA action than the hypothalamus-pituitary axis.