Some new aspects of dexamethasone-induced cleft palate in mice

Pregnant mice were treated intramuscularly with dexamethasone in a single dose of 10 or 50 mg/kg once on day 13 of pregnancy at one of 4 fixed times. On day 18 palate condition of live fetuses and the number of resorptions were recorded and the relation of the incidence of palatal defect and serum corticosterone level was examined. The results suggest that there are different susceptibilities to teratogen-induced cleft palate during a 24-h period. The frequency of cleft palate was increased among term fetuses when there was a drop in the endogenous glucocorticoid of the dams.