Glucocorticoid inhibition of RNA synthesis responsible for cleft palate in mice: a model.

A study was undertaken to elucidate the molecular mechanisms by which glucocorticoids induce cleft palate in mice. It was hypothesized that a compound such as triamcinolone acetonide inhibits mRNA synthesis; that this results later in depressed protein synthesis; and that the latter is ultimately responsible for slowed palate formation and cleft palate. Support for the model derives from the fact that the palatine shelves rise and fuse 3-4 days after the most sensitive time of administration of steroid; RNA synthesis was markedly inhibited 6-24 hr after its administration; and coadministration of cycloheximide partially reversed the tendency toward cleft palate formation.