Induction of cleft palates by triamcinolone acetonide: re-examination of the problem.

We have examined the uptake of 3H-triamcinolone acetonide (3H-TAC) into various maternal and embryonic tissues of A/J mice. We report that the fetal tissues were able to retain TAC for long periods, although the concentrations of TAC in the maternal tissues were significantly lower. We have also examined the binding of 3H-TAC both to nuclei and cytosols from maxillary processes. We report that 3H-TAC can bind to chromatin both at low and high affinity. This leads to the isolation of two chromosmal protein fractions containing bound 3H-TAC. Therefore, triamcinolone acetonide is favorably retained in fetal tissues by its ability to bind tightly to chromatin.