General Description of Volume: Volume 51 includes reviews papers on cyclic AMP, kinases, polypeptide hormones, steroid hormone receptors, related genes, and members of the gene family. General Description of Series: Under the capable and qualified editorial leadership of Dr. Gerald Litwack, Vitamins and Hormones continues to publish up-to-date synthetic reviews of interest to endocrinologists and biochemists. Others interested in the structure and function of biologically active molecules like hormones and vitamins will, as always, turn to this series for comprehensive reviews by leading contributors to this and related disciplines. First published in 1943, Vitamins and Hormones is the longest-running serial published by Academic Press. In the early days of the serial, the subjects of vitamins and hormones were quite distinct. Now, new discoveries have proved that several of the vitamins function as hormones and many of the substances inferred by the title of the Serial function in signal transduction processes. Accordingly, the editor-in-chief has expanded the scope of the serial to reflect this newer understanding of function-structure relationships in cellular communication. The newly modified editorial board now reflects expertise in the field of hormone action, vitamin action, X-ray crystal structure, physiology and enzyme mechanisms. Vitamins and Hormones continues to publish up-to-date synthetic reviews of interest to endocrinologists and biochemists. Others will increasingly turn to this series for comprehensive reviews by leading researchers in this and related disciplines.