TANAKA Akiyo Graduate School of Medical Sciences, Kyushu University Assistant Professor, 女学院・医学系研究科, 講師 (10136484)
MAKITA Yuji Graduate School of Medical Sciences, Kyushu University Assistant Professor, 女学院・医学系研究科, 助教授 (30209407)
MASUDA Yoshito Daiichi Collage of Pharmaceutical Sciences, Professor, 教授 (20069743)
OMURA Minoru Graduate School of Medical Sciences, Kyushu University Instructor, 女学院・医学系研究科, 助手 (50243936)
HIRATA Miyuki Graduate School of Medical Sciences, Kyushu University Instructor, 女学院・医学系研究科, 助手 (30156674)
One μ g/kg body weight/day of 1,2,3,4,6,7-hexachlorinated naphthalene (1,2,3,4,6,7-HxCN) was given to pregnant rats on Days 14-16 of gestation and the effects on the reproductive system of their male offsprings were examined at various phases of sexual maturation. Sperm count in the cauda epididymidis did not change in 1,2,3,4,6,7-HxCN group at postnatal day 89, the age of sexual maturity, but increased to about 180% of the control value at postnatal day 62. In addition, homogenization-resistant testicular spermatid increased to about 160% of the control value at postnatal day 48 and % post-meiotic tubules increased to about 190% of the control value at postnatal day 31 in this group. These results indicated that the onset of spermatogenesis was accelerated in 1,2,3,4,6,7-HxCN group. Serum concentrations of LH and FSH had already reached the plateau level or maximum level at postnatal day 31 in 1,2,3,4,6,7-HxCN group, suggesting that the onset of LH and FSH secretions from the pituitary gland was also accelerated and that this endocrine disruption was the cause of early onset of spermatogenesis in this group. In the fat of 1,2,3,4,6,7-HxCN-treated dam, 5.75 ± 2.81 ppb of 1,2,3,4,6,7-HxCN was detected at the weaning of their offsprings. This concentration was not so high compared with that in human adipose tissue indicating that 1,2,3,4,6,7-HxCN-induced endocrine disruption may actually occur in human.