Teratogenic effect of 6‐azauridine in rats

Abstract

Abstract The embryotoxic effects of 6‐azauridine, given during different periods of gestation in rats, are described. Administration on days 1–6 was lethal or without any effect. Days 6–12 was the period of greatest embryonic susceptibility. 330 and 110 mg/kg caused 100% resorption; 36 mg/kg embryolethality in 85%, teratogenicity in 53.8%. After 12 mg/kg 5.8% of the fetuses were malformed, mostly with encephalocele and gastroschisis. Administered on days 12–18, 3,g/kg was 100% embryolethal and 1 g/kg 32.7% embryolethal and 100% teratogenic, causing malformations of extremities. After 330 mg/kg 65.2% of fetuses survived without any visible damage. Following single administrations of 6‐azauridine embryolethality was commonest after 3 g/kg on days 8 and 11. The teratogenic effect was best expressed after 3 g/kg on day 15, 1 g/kg on day 13, and 330 mg/kg on day 8. Malformations observed were cleft palate, gastroschisis, and dysmelia.