In utero reproductive study in rats exposed to nonylphenol

Alkylphenol ethoxylates are widely used non-ionic surfactants. Nonylphenol ethoxylate constitutes 82% of the production of all alkylphenol ethoxylates and the breakdown product of nonylphenol ethoxylate, nonylphenol (NP) has been shown to be estrogenic in both in vitro and in vivo screening assays. To determine the potential reproductive toxicity of NP, a one-generation in utero study was conducted, Rats were dosed from gestation day 11 through 1 8 with NP at 3, 15, or 75 mg/kg/day or diethylstilbestrol (DES) at 30 mug/k g/day. DES was used as a positive control. Both substances were given orall y by gavage. Male offspring were sacrificed at postnatal day (PND) 11, 21, or 110 and reproductive parameters were evaluated. Pup birth weight and bod y weight and percent motile sperm at age of 110 day were significantly redu ced by DES. The absolute weight of the right epididymis was significantly r educed in the DES group. The absolute weight of the right epididymis were a lso significantly decreased in the animals exposed to 75 or 15 mg/kg/day NP , effects which disappeared when organ weight was related to body weight. T his study showed a dose-dependent effect of nonylphenol on male reproductiv e development at doses of 75 and 15 mg/kg bw/day based on absolute epididym al weight. (C) 2001 Elsevier Science Inc. All rights reserved.