Onset of spermatogenesis is accelerated by gestational administration of 1,2,3,4,6,7-hexachlorinated naphthalene in male rat offspring

We treated pregnant rats with 1 mu g/kg body weight/day 1,2,3,4,6,7-hexachl orinated naphthalene (1,2,3,4,6,7-HxCN) on days 14-16 of gestation and exam ined the effects on the reproductive systems of their male offspring at var ious phases of sexual maturation. Sperm count in the cauda epididymidis did not change in 1,2,3,4,6,7-HxCN-treated rats on postnatal day 89, the age o f sexual maturity, but the sperm count in the cauda epididymidis did increa se to approximately 180% of the control value on postnatal day 62. In addit ion, homogenization-resistant testicular spermatids increased to approximat ely 160% of the control value on postnatal day 48, and the percent of postm eiotic tubules increased to approximately 190% of the control value on post natal day 31 in this group. These results indicate that the onset of sperma togenesis was accelerated in the 1,2,3,4,6,7-HxCN rats. Serum concentration s of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) had al ready reached the maximum level on postnatal day 31 in the 1,2,3,4,1;,7-HxC N group, suggesting that the onset of LH and FSH secretions from the pituit ary gland was also accelerated and that this endocrine disruption was the c ause of early onset of spermatogenesis in this group. In the fat of 1,2,3,4 ,6,7-HxCN-treated darns, 5.75 +/- 2.81 ppb 1,2,3,4,6,7-HxCN was detected wh en offspring were weaned. This concentration was 5-10 times higher than tha t found in human adipose tissue.