Serum dioxin-like activity is associated with reproductive parameters in young men from the general Flemish population.
BACKGROUND
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and some related environmental contaminants are aryl hydrocarbon receptor (AhR) ligands that exert reproductive and developmental toxicity in laboratory animals. In humans, fertility-related effects are less documented.


OBJECTIVE
The aim of this study was to investigate the relationship between dioxin-like biological activity in serum and parameters of reproductive status in men from the general population 5 months after a polychlorinated biphenyl and dioxin food-contamination episode in Belgium.


METHODS
In the framework of the cross-sectional Flemish Environment and Health Study (FLEHS), we recruited 101 men 20-40 years of age and evaluated sperm parameters, measured sex hormones, and gathered information on a number of lifestyle factors. In addition, we determined the AhR-mediated enzymatic response elicited by individual serum samples and expressed it as TCDD equivalent concentrations (CALUX-TEQs) using an established transactivation assay.


RESULTS
Age (p = 0.04) and the frequency of fish (p = 0.02) and egg (p = 0.001) consumption were independent positive determinants of serum dioxin-like activity. After correcting for possible confounders, we found that a 2-fold increase in CALUX-TEQ > 16 pg/L was associated with a 7.1% and 6.8% (both p = 0.04) decrease in total and free testosterone, respectively. We also observed a more pronounced drop in semen volume of 16.0% (p = 0.03), whereas sperm concentration rose by 25.2% (p = 0.07). No relationship was found with total sperm count or sperm morphology.


CONCLUSIONS
These data suggest an interaction of dioxin-like compounds with the secretory function of the seminal vesicles or prostate, possibly indirectly through an effect on testosterone secretion, at levels not affecting spermatogenesis as such.
Dhooge
Willem
W
Department of Endocrinology, University Hospital Ghent, Belgium. Willem@Dhooge.org
van Larebeke
Nicolas
N
Koppen
Gudrun
G
Nelen
Vera
V
Schoeters
Greet
G
Vlietinck
Robert
R
Kaufman
Jean-Marc
JM
Comhaire
Frank
F
D000328:Adult; D000818:Animals; D001530:Belgium; D015415:Biomarkers; D045744:Cell Line, Tumor; D004032:Diet; D004147:Dioxins / Q000097:blood*; D004785:Environmental Pollutants / Q000097:blood*; D004958:Estradiol / Q000097:blood; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007265:Inhibins / Q000097:blood; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D051381:Rats; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D013076:Sperm Count; D013739:Testosterone / Q000097:blood*
D015415:Biomarkers; D004147:Dioxins; D004785:Environmental Pollutants; D018336:Receptors, Aryl Hydrocarbon; D012738:Sex Hormone-Binding Globulin; C422364:inhibin B; D013739:Testosterone; D004958:Estradiol; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone