Effects of persistent chlorinated hydrocarbons on reproductive tissues in female rabbits

The female rabbit was used to study (i) accumulation of lipophilic chlorinated hydrocarbons in genital tract tissues and (ii) subsequent morphological and functional effects after long-term low-dose exposure. Polychlorinated biphenyl (PCB), 1,1-di(p-chlorophenyl)-2,2,2-trichloroethane (DDT) and gamma-hexachlorocyclohexane (gamma-HCH) (dosages: 4, 3 and 0.8 mg per kg body weight, respectively) and a combination of these three components (and dosages) were administered to sexually mature rabbits over a period of 12-15 weeks. The animals were killed shortly before and at various times after ovulation. Accumulation of chlorinated hydrocarbons was high in ovarian, oviductal and uterine tissues, in follicular fluid and clearly detectable in uterine secretions. In follicular fluid, the concentration and patterns of congeners and isomers of PCB and DDT were distinctly different from serum. DDT- and gamma-HCH-treated animals showed a significantly reduced ovulation rate (P < 0.002 and 0.05, respectively). During early pregnancy DDT decreased serum progesterone levels and changed the protein pattern of uterine secretion. Functional effects, however, were much less expressed compared with the highly significant accumulation of the persistent organochlorines in the genital tract.