Identification of Rat foreskin biomarkers of in utero dibutyl phthalate exposure [Affymetrix]

Dibutyl phthalate was administered to pregnant Sprague Dawley rats from gestational days 16-20 at either a 100 mg/kg/day or 500 mg/kg/day dose level. This timeframe covers the reproductive masculinization window which corresponds to increased androgen signalling. Dibutyl phthalate has been shown to disrupt testosterone production leading to male reproductive abnormalities. As such, we selected this exposure window for our study and examined gene expression changes in the male rat foreskin, which expresses the androgen receptor. We collected tissue samples at both gestational day 20 to identify gene expression changes immediately after exposure, and postnatal day 5 to identify gene expression changes persisting after birth using microarray analysis (Illumina RatRef 12 Bead Chips). To determine whether gene expression changes were brought on by decreased androgen signalling or additional effects of dibutyl phthalate exposure, we exposed rats to the potent androgen receptor antagonist flutamide (5 mg/kg/day) during the same period of development. Gene expression changes were compared to determine which were brought on by disruption of androgen signalling and which were the result of other aspects of chemical exposure.

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