The field of steroid hormone action has continued to expand into the realm of molecular biology at a pace even faster than most of us ever imagined. techniques of molecular biology have made it possible to clone The hormone-regulated genes and to examine steroid-receptor interactions with these genes. Nucleotide sequences of these genes, which show preferential binding of steroid receptors, have been identified. These results are complemented by the identification of chromatin acceptor proteins, which also show preferential binding for steroid-receptor complexes. Thus, one can envision the day when cloned genes, purified acceptor proteins, and receptor-steroid complexes will be recombined in vitro to form a functional unit. Cellular localization of steroid receptors has undergone recent revision, and it now appears that receptors are localized primarily in the nuclear compartment. These findings, although controversial, will lead to a reassessment of many of the previous concepts of steroid-receptor interactions and regulation. The way in which these observations at the of physiology, molecular and cellular levels fit into the overall scheme development, and evolution are continuing to progress, and the future promises some very exciting syntheses of understanding at all levels of biological organization. The third Meadow Brook Conference on hormones was held in order to bring together investigators who will undoubtedly contribute heavily to this future synthesis and to permit a free exchange of ideas and concepts as they relate to the current state-of-the-art in molecular endocrinology. Spring 1986 ARUN K. Roy JAMES H. CLARK Contents Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The first Meadowbrook Symposium was held in 1978 and during the intervening ten years our knowledge concerning how steroid hormones function at the level of gene expression has advanced by leaps and bounds. In this volume, which sum marizes our fourth meeting, these advances are very evident. What seemed like science fiction ten years ago has become commonplace science. Who would have imagined that we could synthesize a nucleotide sequence that binds a specific steroid receptor and acts as a controlling element for gene expression? No one; but as is evident from the results reported in several chapters, this technique is yielding a wealth of information. Using these and other techniques it has become apparent that gene transcription is controlled by interactions between transacting factors and DNA recognition sequences (response elements). These transacting factors appear to be members of a large gene family that includes steroid hormone receptors, transcription factors, protooncogenes and homeobox proteins. Thus a great deal has been learned, but as usual, questions remain. Many of these questions are posed by the findings and observations found in several chapters in this volume. Non hormone binding forms of steroid receptors and their relevance to receptor down regulation, recycling and biological response remain a mystery. The quantitative relationship between receptor binding and biological response still presents agonizing problems. These and many other intriguing questions are discussed in this volume and set the stage for what should be a most rewarding time in endocrinology. Winter 1989 ARUN K."