MULTIGENERATIONAL STUDY OF THE EFFECTS OF CONSUMPTION OF PCB-CONTAMINATED CARP FROM SAGINAW BAY, LAKE-HURON, ON MINK - 3 - ESTROGEN-RECEPTOR AND PROGESTERONE-RECEPTOR CONCENTRATIONS, AND POTENTIAL CORRELATION WITH DIETARY PCB CONSUMPTION

Mink (Mustela vison) were fed diets containing ocean fish (control die t, O.D ppm polychlorinated biphenyls, PCBs) or Saginaw Bay carp to pro vide 0.25, 0.5, or !.O ppm PCBs to examine the effect of PCBs on homeo stasis of binding sites for ovarian steroid hormones. Ranch-raised min k fed Great lakes fish contaminated with PCBs, or treated with PCBs di rectly, have demonstrated reproductive impairment including anovulatio n, fetal resorption, delayed ovulation, increased gestation, and decre ased litter size. Previous studies have demonstrated that estrogen and progesterone levels are unaltered in mink treated with PCBs, suggesti ng that the effect of PCBs on reproduction is not mediated through alt erations in hormone homeostasis. In vitro studies have demonstrated th at the most likely means by which PCBs exert antiestrogenic ability is through a downregulation of the estrogen receptor in normally estroge n responsive tissues such as liver and uterus. Hepatic and uterine est rogen binding site concentrations were measured in female mink consumi ng diets containing PCBs for up to 18 mo at up to 1 ppm. Hepatic estro gen binding site concentrations generally decreased with increasing di etary PCB concentrations. Uterine estrogen binding site concentration did not decrease in these animals. Uterine progesterone receptor conce ntration also did not change with increasing PCB consumption. In total , the response of hepatic and uterine estrogen and uterine progesteron e binding sites in mink fed diets containing Saginaw Bay carp suggests that concentrations of PCBs available to uterine tissue may not have been sufficient to decrease uterine estrogen receptor, despite their e ffect on hepatic estrogen receptor.