Quantitative und histologische Untersuchungen an der fetalen und mütterlichen Schilddrüse der Ratte unter Propylthiouracil

Abstract

Introduction No quantitative and morphometric studies based on a larger sample of thyroid glands from young rats whose mothers had been treated with thyrostatic drugs during pregnancy have been published so far. Material and Methods A total of 24 female Sprague-Dawley-rats were divided into 2 control groups and 2 test groups. In test I the animals were given 10 mg of PTU/100 g body weight between the 5th and 16th day of pregnancy, in test II the same dose was administered from the 5th to the last day of pregnancy. The weight of 265 young rats born alive was determined with an error of 0.1 g, the weights of the thyroids both of the newborn rats and their mothers were determined with an error of 0.05 mg. Fixation was achieved in Bouin's solution. The thyroid follicles were measured with an ocular micrometer in 4 μ HE-sections. Mitoses were counted and epithelial alterations evaluated histologically. Statistical evaluation was performed for body and thyroid weights by variance analysis and by the Duncan-test. Results With increasing dosage of PTU there is a highly significant decrease in body weight of the newborn rats (p > 0.001). The thyroid weights, on the other hand, both in the newborn rats and their mothers show a highly significant increase with increasing dosage (p > 0.001). The follicular diameter shows no changes in newborn rats, but decreases in their mothers depending on the dosage. Histologically an increase of mitotic figures as well as of cell and nucrear pleomorphism is seen both in newborns and their mothers in relation to the dosage. Discussion The increase in weight of thyroid glands under PTU is the result of a dose-related increase in the number of follicles and cells. There is, in addition, a highly significant retardation of body growth in fetal rats, also related to dosage. The danger of thyrostatic therapy during pregnancy is pointed out.