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PRESENTED AT NC SOCIETY OF TOXICOLOGY MEETING IN RESEARCH TRIANGLE PARK, NC ON 2/16/2006: PERIPUBERTAL PROCHLORAZ EXPOSURE STRONGLY INHIBITS TESTOSTERONE PRODUCTION, BUT HAS WEAK EFFECTS ON PUBERTY
BLYSTONE, C., J. FURR, C. R. LAMBRIGHT, K. HOWDESHELL, B. RYAN, V. S. WILSON, G. LEBLANC, AND L. E. GRAY. PRESENTED AT NC SOCIETY OF TOXICOLOGY MEETING IN RESEARCH TRIANGLE PARK, NC ON 2/16/2006: PERIPUBERTAL PROCHLORAZ EXPOSURE STRONGLY INHIBITS TESTOSTERONE PRODUCTION, BUT HAS WEAK EFFECTS ON PUBERTY. Presented at NC Society of Toxicology, Research Triangle Park, NC, February 16, 2006.
Prochloraz (PCZ) is an imidazole fungicide that inhibits steroidogenesis and acts as an androgen receptor antagonist. We hypothesized that pubertal exposure to prochloraz would delay preputial separation and development of reproductive organs. Sprague Dawley rats were dosed with PCZ (0, 31.25, 62.5, 125 mg/kg) from post natal day (PND) 23 to 51. The timing of preputial separation (PPS), mid- and post-puberty organ weights, and serum hormone levels (n=8-10) were determined. Testicular steroid production was measured ex vivo. The start and completion of PPS were delayed significantly in the 125mg/kg treatment group. Epididymides and levator ani plus bulbocavernosus muscle (LABC) weights were decreased significantly in the 62.5 and 125mg/kg treatment groups at mid-puberty while the ventral prostate and seminal vesicle weights were decreased in the 125mg/kg group at post-puberty. Serum testosterone and androstenedione levels were significantly decreased as was ex vivo androgen release from testis at all doses. Serum progesterone and 17?-hydroprogesterone levels were significantly increased at most treatment levels. These data demonstrate that PCZ decreases testosterone levels and delays rat pubertal development. However, the treatment effects on testosterone levels were at dose levels well below those that delayed puberty which suggests for PCZ that rather large reductions in serum testosterone may be required to delay puberty. Research supported by NCSU EPA Co-op# CT 826512010. This abstract has been reviewed by the US EPA and does not necessarily reflect US EPA views or policy.