Serum Hormones in Boys Prenatally Exposed to Polychlorinated Biphenyls and Dibenzofurans

Abstract

Polychlorinated biphenyls (PCBs) and dibenzofurans (PCDFs) are persistent environmental pollutants shown to adversely interact with several functions of the endocrine system. In 1978-1979, over 2000 Taiwanese people ingested rice oil accidentally contaminated with PCBs and PCDFs. This is one of the major toxic exposure episodes that occurred globally and was later called Yucheng (oil disease in Chinese). The children born to exposed Yucheng women were therefore exposed in utero to high doses of PCBs/PCDFs. In 1995, 60 Yucheng and 61 control boys participated in physical examination, and serum hormones were measured by radioimmunoassay (RIA). Age, body weight, body height, Tanner status, testicular size, serum luteinizing hormone (LH), prolactin (PRL), thyroxine (T4), triiodothyronine (T3), and thyroid-stimulating hormone (TSH) levels were not statistically different between Yucheng and control boys in the subgroups of before and at the age of puberty. However, the serum estradiol (E2) levels were significant higher in Yucheng boys at the age of puberty. Yucheng and control boys were further divided into two subgroups, those before (age <13 yr) and those at the age of puberty (age > or = 13 yr). There was a decrease of serum testosterone (TT) levels and increase of serum follicle-stimulating hormone (FSH) levels in Yucheng boys at the age of puberty as compared with controls. There was a significant decrease of the square root of TT/E2 and TT/FSH; however, the square root of E2/FSH was increased in Yucheng boys at the age of puberty as compared with controls. Data indicated that prenatal exposure to PCBs and PCDFs may have implications for boys' sex hormone homeostasis at puberty. Further studies are needed to identify the congeners of PCBs/PCDFs responsible for disruption of the endocrine system, as well as the mechanisms of such disruption.

Internal exposure to pollutants and sex hormone levels in Flemish male adolescents in a cross-sectional study: associations and dose–response relationships

“…High-level prenatal exposure to PCBs during the Yucheng incident was positively associated with estradiol but negatively associated with testosterone serum concentrations in boys at puberty (Hsu et al, 2005), whereas Mol et al (2002) reported only weak associations between serum hormone parameters at 14 years of age and the level of prenatal PCB exposure in 196 boys from a Faroese birth cohort. Hagmar et al (2001) did not find a significant correlation between serum levels of PCBs and testosterone in adult men.…”

Environmental chemicals and thyroid function

“…These changes in THs were within normal reference ranges. A study of boys prenatally exposed to high doses of PCBs and polychlorinated dibenzo-p-furans (PCDFs) showed no differences in thyroid function compared with a control group (43). In conclusion, human and wildlife observations point towards subtle, but significant, effects of low-dose PCB exposure on human thyroid function.…”

Environmental Factors and Puberty Timing: Expert Panel Research Needs

“…Neither study found an association between PCB exposure and age at menarche. Last, Yang et al 104 and Hsu et al 105 described no pubertal developmental differences among boys or girls with and without exposure to PCB-and polychlorinated dibenzofuran-contaminated cooking oil.…”