Teratogenic effect of 6‐azauridine in rats

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.