Role of corticosterone in cleft palate formation in methylmercuric chloride-treated mice

Abstract

The effect of simultaneous administration of sodium selenite and methylmercuric chloride on plasma corticosterone, and the effect of adrenalectomy and methylmercuric chloride treatment on the incidence of fetal cleft palate in mice were examined. After 6 consecutive days of treatment, methylmercury (as methylmercuric chloride) at 5 mg/kg per day increased plasma corticosterone to approximately twice the concentration observed in the controls. When administered together, selenium (as sodium selenite) at 125–135 mg/kg per day did not affect the increase of plasma corticosterone induced by methylmercuric chloride. Selenite by itself (125–135 mg selenium/kg per day) resulted in an increase of approximately 50% over the controls. Sham operation or adrenalectomy of mice on Day 7 of pregnancy did not result in a significant incidence of cleft palate in the fetuses. However, the administration of methylmercury (5 mg/kg per day) on Days 11, 12, and 13 of gestation to the operated mothers resulted in cleft palate in approximately 30% of the fetuses, regardless of the type of operation. The significance of these findings is discussed.