Background:The objective of this study was to determine if human spermatozoa express AHR (dioxin receptor) and ARNT and if mRNA levels for these transcription factors correlate with sperm concentration, motility or morphology.Material/Methods: This was a case-controlled cohort study in which AHR and ARNT mRNA levels in subjects with normal and abnormal semen analysis were compared. Semen analysis was performed by CASA. AHR/ARNT mRNA levels were determined by multiplex RT-PCR using Glyceryl aldehyde 3-phospho dehydrogenase (G3PDH) as an internal control.Results: Human sperm expresses abundant amounts of AHR and ARNT mRNA. There were no differences in AHR and ARNT mRNA levels in subjects with normal and abnormal semen analysis. AHR and ARNT levels did not correlate with sperm concentration, morphology or motility. There was a trend (p=0.07) for lower AHR mRNA expression in sperm of men with severe oligospermia. There was a significant negative correlation (r=–0.42, p<0.05) between sperm AHR and ARNT mRNA.
Conclusions: The presence of AHR in sperm provides a mechanism by which environmental dioxins, polycyclic aromatic hydrocarbons and polyhalogenated biphenyls could directly influence sperm function.

Keywords: Basic Helix-Loop-Helix Transcription Factors, Case-Control Studies, Cohort Studies, DNA Primers - chemistry, Dioxins - metabolism, Hydrocarbons - chemistry, Infertility, Male, Protein Binding, RNA, Messenger - metabolism, Receptors, Aryl Hydrocarbon - biosynthesis, Reverse Transcriptase Polymerase Chain Reaction, Semen - metabolism, Spectrophotometry, Spermatozoa - metabolism, Transcription Factors - biosynthesis, Transcription, Genetic, ARNTL Transcription Factors, Basic Helix-Loop-Helix Transcription Factors, Case-Control Studies, Cohort Studies, DNA Primers - chemistry, Dioxins - metabolism, Hydrocarbons - chemistry, Infertility, Male, Protein Binding, RNA, Messenger - metabolism, Receptors, Aryl Hydrocarbon - biosynthesis, Reverse Transcriptase Polymerase Chain Reaction, Semen - metabolism, Spectrophotometry, Spermatozoa - metabolism, Transcription Factors - biosynthesis, Transcription, Genetic