Morphological and functional disorders of the immature rat uterus after postnatal exposure to benz[a]anthracene and benzo[k]fluoranthene

We investigated the effects of postnatal exposure to benz[a]anthracene (B[a]A) and benzo[k]fluoranthene (B[k]F) on the development of the rat uterus. Neonates were injected on each postnatal days 1-14 with B[a]A (0.1, 1.0 or 10.0 mg/kg), B[k]F (0.1, 1.0 or 5.0 mg/kg), ethynylestradiol (EE; 1.0 μg/kg) or a vehicle. The rats were killed on day 23. All doses of B[a]A and B[k]F induced a reduction of the uterine weight, a reduction of the estrogen receptor α expression in the luminal epithelium, glandular epithelium and stromal cells. Moreover, the uterotrophic response to EE (3-day administration of 1.0 μg/kg on postnatal days 20-22) in rats exposed to B[a]A, B[k]F and EE was lower than in controls. The study showed that postnatal exposure to B[a]A and B[k]F resultes in morphological and functional disorders of the immature rat uterus.