Maternal and offspring toxicity but few sexually dimorphic behavioral alterations result from nonylphenol exposure

Nonylphenol ethoxylates are used in the production of surfactants and are f ound in numerous manufactured substances, para-Nonylphenol (NP) is a suspec ted endocrine disrupter, exhibiting estrogen-like activity and might cause alterations with developmental exposure. To evaluate such effects, pregnant Sprague-Dawley rats consumed diets containing 0 (n = 11), 25 (n = 10), 500 (n = 10), or 2,000 (n = 9) ppm NP beginning on gestational day (GD) 7. At postnatal day (PND) 21, offspring continued on the same maternal diets unti l PND 77 and were evaluated for behavioral alterations (open-field activity at PNDs 22-24, 43-45, 64-66, play behavior at PND 35, running wheel activi ty at PND 63-77, flavored solution intake at PND 69-75). During pregnancy a nd lactation, darns in the 25-, 500-, and 2,000-ppm groups consumed 9 to 25 % less food, which was associated with a 17% less weight gain during GDs 1 to 21 in dams of the 2,000-ppm group, although this effect was not statisti cally significant. Gestation duration, birth weight, sex ratio of live pups , and number of live or dead pups per litter did not differ between treatme nt groups. Offspring body weight and food consumption were decreased in the ?,000ppm group beginning at PNP 28; however, an effect of feed aversion co uld not be eliminated. Behavioral assessments of offspring indicated no con sistent NP-related effects in open-field activity at PNDs 22-24, 43-45, and 65-67 nor in running wheel activity at PNDs 63-75. Play behavior at PND 35 and intake of a 0.3% saccharin-flavored solution at PNDs 69-71 did not dif fer with respect to treatment groups. However, intake of a 3% sodium-flavor ed solution at PNDs 73-75 was significantly increased in offspring of the 2 ,000-ppm group and intake of regular water during this same time was also s ignificantly increased. These results indicate that developmental NP treatm ent results in maternal and offspring toxicity as evidenced by decreased fo od intake and weight gain. However, behavioral alterations were evident onl y in increased intake of a sodium solution. (C) 2000 Elsevier Science Inc. All rights reserved.