This study was conducted to investigate the applicability of an in vitro technique for maturation, fertilization, cleavage, and growth to blastocysts of bovine oocytes to investigate reproductive toxicologic effects. During maturation, the oocytes were exposed to the di-ortho-substituted PCB congener 2,2',4,4',5,5'-CB (PCB 153) in the three concentrations 0.84 ng/mL, 8.4 ng/mL, and 84 ng/mL or to the non-ortho-substituted PCB congener 3,3'4,4',5-CB (PCB 126) in the three concentrations 1.006 pg/mL, 10.06 pg/mL, and 100.6 pg/mL and compared with control groups. PCB 153 had no effect on maturation but resulted in a reduced proportion of oocytes that cleaved at the highest concentration. There were no differences in blastocyst development among groups. PCB 126 resulted in a reduction in maturation percentage at the highest concentration and in blastocyst development at all concentrations. These results demonstrated adverse effects of PCB congeners on bovine oocytes and showed that this system can be used to evaluate toxic effects on oocytes and preimplantation-stage embryos.

Animals↗

PubMedDate not supplied

Distribution and elimination of hexachlorobenzene (HCB) after single oral exposure in Japanese quail (Coturnix coturnix japonica).

The distribution and excretion of hexachlorobenzene (HCB) after administration to quails of a single oral dose of 4.5 microCi [14C] HCB per 100 g body weight was studied by whole-body autoradiography and liquid scintillation counting. Radiolabeled HCB was distributed throughout the body in 2 h. Peak levels were found 4-8 d after administration, with the highest concentrations in the subcutaneous and abdominal fat, uropygial gland, bone marrow, adrenals, ovarian stroma, and liver, in that order. After 3 wk, substantial amounts of radiolabeled substance were present only in the adipose tissue and the uropygial gland. The main routes of excretion were the egg yolk, uropygial gland, and bile. About 75% of the administered dose was excreted through the egg yolk and about 25% in the feces.

Administration, Oral↗