Cysteine interference with chlorambucil-induced teratogenesis in the rat

Pregnant rats were given a single injection of cysteine prior to exposure to chlorambucil on day 12 of gestation. This treatment caused a significant 6-fold increase in structurally normal surviving fetuses when compared to chlorambucil alone. The abnormal survivors demonstrated a less severe syndrome of anomalies that was not similar to the patterns of defects associated with chlorambucil treatment on other days of gestation.