Publisher Summary This chapter discusses the cellular receptors and mechanisms of action of steroid hormones. The chapter covers those aspects related to the action of estrogens, androgens, progestins, glucocorticoids, and mineralocorticoids in vertebrates. The search for receptor proteins for these steroid hormones in most instances follows a unique pattern which includes (1) study of the uptake and retention of a radioactive hormone; (2) identification of the hormone presumed to be the active form; (3) detection and isolation of a specific protein that binds an active steroid but not an inactive steroid with a high affinity, and exists in larger amounts in target cells than in insensitive cells; and (4) demonstration that steroid antagonists can interfere with receptor binding of an active steroid. Studies on steroid receptors have been recently extended to several more biodynamic aspects such as qualitative and quantitative analysis of receptor proteins and their relation to biological responses of target cells and to some clinical situations. Concentrated efforts, however, are being made to discover the molecular mechanism whereby a steroid receptor complex may participate in the regulation of gene expression of the target cells. For this reason extensive studies have been carried out on the interaction of the steroid-receptor complex and the nuclear components of target cells. The chemical structures of many representative steroid hormones, natural or synthetic, and their antagonists are shown.

Cellular receptors and mechanisms of action of steroid hormones.

Photoaffinity labeling of glucocorticoid receptors.

Immunocytochemical demonstration of glucocorticoid receptors in different cell types and their translocation from the cytoplasm to the cell nucleus in the presence of dexamethasone.

It has been known for some time from neuroendocrine and behavioral studies that the brain is both a master controller of endocrine function and a target for these endocrine secretions. There exist complex feedback interactions between endocrine secretions and the brain which not only control the secretion of hypothalamic and pituitary hormones but also influence neural activity underlying behavior. It is only quite recently that we have come to appreciate the role of the entire limbic brain, and not just the hypothalamus, in these endocrine-brain interactions.

Putative Glucocorticoid Receptors in Hippocampus and Other Regions of the Rat Brain

http://www.jbc.org/content/254/5/1537.full.pdf

A.D. Abraham

Papers

Corticosteroid binding macromolecules in the nucleus and cytosol of rat thymus cells