Hormonal Domains of Response: Actions of Glucocorticoid and Thyroid Hormones in Regulating Pleiotropic Responses in Cultured Cells

Abstract

Publisher Summary This chapter discusses the pleiotropic responses of thyroid and glucocorticoid hormones in cultured hepatoma cells (H35 and HTC) and cultured anterior pituitary cells (GH3). Both hormones influence a limited and highly specific domain in each cell type. Approximately 1% or less of the detected gene products are affected by each hormone. Evidence presents that there is only a very limited overlap in the glucocorticoid domains of HTC and H35 cells, as only tyrosine amino-transferase is induced by dexamethasone in both cell types. There can be heterogenity in glucocorticoid domains among parenchymal cells from livers of the same strain of rats. Alternatively, differences in the levels of expression of domain members or transformation-dependent influences on the glucocorticoid domains of different cell lines can account for these results. In addition, the glucocorticoid hormone domains between GH3 and either HTC or H35 cells are almost completely non-identical. Overlap between the glucocorticoid and thyroid hormone domains has been demonstrated in GH3 cells. The two hormones can regulate the same gene product in one of three ways: conduction, co-repression, or induction by one hormone and repression by the other. Both glucocorticoid and thyroid hormones are capable of inducing and repressing individual domain members.