Effects of in utero exposure to 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153) on somatic growth and endocrine status in rat offspring.

Exposure to polychlorobiphenyl (PCB) mixtures at an early stage of development has been reported to affect endocrine glands; however, little is known about the precise toxicological properties of individual PCB. The present study was undertaken to determine whether prenatal exposure to 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153), a di-ortho-substituted non-coplanar congener, affects postnatal development in rat offspring. Pregnant Sprague-Dawley rats (Crj: CD (SD) IGS) were given PCB 153 (0, 16, or 64 mg/kg/day) orally from gestational day (GD) 10 through GD 16, and developmental parameters in the male and female offspring were examined. We found no dose-dependent changes in body weight, body length (nose-anus length), tail length, or the weights of kidneys, testes, ovaries and uterus in offspring at 1 or 3 weeks of age. Liver weights were increased in the PCB 153-treated groups, although we observed a significant difference only in males. Anogenital distance was unaffected in the PCB 153-treated groups. We observed a significant dose-dependent decrease in the plasma concentrations of thyroxine and tri-iodothyronine, whereas those of thyroid-stimulating hormone were not significantly changed. In addition, there were no dose-dependent changes in plasma concentrations of growth hormone and insulin-like growth factor-I in any dose group. These findings suggest that prenatal exposure to PCB 153 (GD 10-16, 16-64 mg/kg/day) may alter the thyroid status in rat offspring to some extent without affecting somatic growth or its related hormonal parameters.