Abstract
In an in vitro model, cortisol inhibits a precisely timed process of palatal development, the lysosomally mediated cell death of the medial edge palatal epithelium. These steroid effects occur only in palatal shelves from mouse strains with high incidences of corticosteroid-induced cleft palate. In studies in vivo using steroid-sensitive mice, corticosteroid delays shelf elevation but does not prevent shelf contact and alters lysosomal enzyme distribution in the medial edge palatal epithelia. Thus, susceptibility to corticosteroid-promoted palatal clefting is correlated with the inhibition of programmed cell death in the medial edge epithelium in vitro and in vivo.
