Dynamics of Steroid Hormone Receptor Action

The steroid hormones-estrogens, progestins, androgens, glucocorticoids, and mineralocorticoids-are chemically quite simple molecules, yet their biological activities are exquisitely specific. Their diverse effects include metabolic, morphological, and behavioral changes. At least part of their hormonal specificity resides in the fact that different tissues contain proteins that selectively bind only certain classes of active steroids; hence, the tissue selects the hormone with which it will interact by possessing high affinity binding proteins, or receptors, for a particular class of steroid hormones. Here I review recent information on (a) the multihormonal regulation of steroid hormone receptors and steroid hormone action in selected tissues and (b) the temporal and quantitative relationships between hormone receptor binding and the stimulation of biological responses in target tis­ sues. I discuss only briefly some recent advances in the biochemistry of steroid hormone receptors since several excellent reviews have covered the state of knowledge through 1976 (15, 41, 55, 114). In view of my own interests and because this review serves as a prelude to reports on the reproductive system, I emphasize .receptors for the sex steroid hormones, in particular the estrogen receptor.