Neonatal exposure to zearalenone causes persistent anovulatory estrus in the rat

The effect of neonatal administration of zearalenone on the female reproductive system was studied in the rat. A single subcutaneous injection of 1.0 mg zearalenone to 3- or 5-day-old rats caused persistent vaginal estrus in adulthood. Ovaries in these animals contained many large follicles but no newly formed corpora lutea. The same effects were observed in rats which had received 100 micrograms estradiol-17 beta in the neonatal period. Most rats which had received 100 micrograms zearalenone or 10 micrograms estradiol-17 beta showed regular 4-day estrous cycles and had newly formed corpora lutea in their ovaries. These results demonstrate that neonatal exposure to zearalenone produced persistent anovulatory estrus in the rat, the potency being about one tenth that of estradiol-17 beta.