EN
Teratogenic effects of the anticonvulsant drug valproic acid (VPA) on the development of rat embryos during early stage of organogenesis were studied using whole embryo culture technique. Embryos with 0-3 somites were exposed in culture to 10, 50 and 100 μg/ml VPA. Growth and development were retarded in embryos exposed to 50 and 100 μg/ml. Drug induced anomalies included open neural tube, irregular somites, and asymmetrically enlarged forebrain. The "no-observed-adverse-effect-level" (NOAEL) was 10 μg/ml VPA.