Effects of Aflatoxin B1 on Pregnant Inbred Sprague-Dawley Rats and Their F1 Generation. A Contribution to Transplacental Carcinogenesis

Aflatoxin B1 had a carcinogenic effect on pregnant inbred SD rats. After ip application from the 15th to the 18th or from the 18th to the 21st days of pregnancy, increased numbers of benign and malignant tumors were found in aflatoxin B1-treated mother animals in comparison to saline-treated controls. Aflatoxin B1 affected more organs than just the liver; tumors were found in a variety of other sites, particularly the digestive tract, urogenital system, and central and peripheral nervous systems. Aflatoxin B1 paased the placental barrier and damaged the fetus. Litter size, occurrence of stillbirths, and average birth weight were investigated in the F1 generation (827 test animals, 113 controls). Stillbirths were particularly evident when aflatoxin B1 was given from the 15th to the 18th days of pregnancy; application during a later period reduced the number of stillbirths to about half of this number. Additional postnatal treatment of the F1 generation led to further deaths during the lactation period. The combination of late fetal and early postnatal administration of aflatoxin B1 proved to be particularly detrimental. Aflatoxin B1 induced a broad spectrum of benign and malignant tumors in the 484 surviving teat animals of the F1 generation as compared with 113 controls. Similar to the pattern in mother animals, tumors occurred mainly in the digestive tract, urogenital system, and central and peripheral nervous systems. Hyperplasias and cysts were observed in various organs. The tumor yield in the endocrine organs was also higher percentagewlse in aflatoxin B1-treated rats than in F1 controls. Transplacental passage of aflatoxin B1 alone was sufficient for tumor production; however, additional postnatal applications increased the tumor yield. Life expectancy in test animals as compared with controls showed no significant differences.