Vitamin A Induction of Cleft Palate

Abstract

Both retinoic acid and retz'nyl acetate, administered in high doses on days 13—15 of gestation, are capable of causing a 90 per cent incidence of cleft palate in Charles River rats. However, an attempt to develop an in viva rabbit model system for the induction of clefts via hypervz'taminosz's A was unsuccessful. In the rat, the retinoic acid form of vitamin A is the more potent teratogen, inducing clefts at less than half the dose required to produce them with retinyl acetate. Histologic examination of fetal rat heads confirmed the biochemical evidence that retinoic acid is the more potent teratogen. Both forms of vitamin A prevented palatal shelf reorientation from occurring at the correct gestational age. The-retinyl acetate treatment delayed the rotation for approximately 12 hours, the retinoic acid for at least 48 hours.