Dose-dependent induction of embryonic abnormalities in vitro by tissue homogenates of placenta and decidua.

Homogenate preparations from normal rat placental and decidual tissue induced abnormalities when included in the culture medium of rat embryos between Day 9.5 and Day 11.5. Abnormal embryos were produced between doses of 2.5 and 4 mg/ml for the placental homogenate and between doses of 1.2 and 4 mg/ml for the decidual homogenate, but were not produced by a solution of bovine serum albumin or by a protein preparation of rat lung tissue at the same concentration. The degree to which the embryos were malformed depended on the dose and which of the two homogenates was used. The decidual homogenate preparation was more pathogenic than the placental homogenate, but both were able to produce neural-tube defects and a severe reduction in embryonic size. The possible association between these findings and some known proteins within such homogenates is discussed.