Histochemical study on the distribution of glucocorticoid receptors in the palatal processes of mouse fetuses

Abstract

Autoradiographic studies were carrid out to elucidate the role of glucocorticoid (GC)-receptors in the induction of cleft palate with GC on mouse fetuses.
Intraamniotic treatments with triamcinolone acetonide (TA) effectively induced cleft palate in the fetuses, indicating a direct teratogenic effect of TA. Autoradiography and binding studies with ⁸H-TA revealed that Karnovsky fixative containing 1% D-catechin was an effective fixative for GC-receptors. After intraamniotic injection of ⁸H-TA, samples were prepared for light microscope autoradiography (LMARG). It was found that the concentration of GC-receptors in the palatal tissues was higher in the stages of higher frequency of cleft palate induction than those of lower frequency. In another series of experiments, the excised palates were incubated in a medium containing ⁸H-TA, and samples were prepared for LMARG and electron microscope autoradiography (EMARG). The results of LMARG showed that the concentration of GC-receptors was higher in the nasal side than in the oral side of the palate. In addition, the results of EMARG were consistent with the currently accepted hypothesis on the recycling of GC-receptors in the target cells.