Hormone Receptors Act by Multiple Interacting Mechanisms

Mechanisms of steroid hormone action have experienced large swings in emphasis and are still being worked out. The discovery that proteins that act as nuclear receptors for steroid, thyroid, and certain other hormones are also transcription factors was intriguing and endocrine investigations could rapidly enter the era of eukaryotic molecular biology. Neurobiologists and others interested in the causation of behavior also realized that some hormone actions in the central nervous system (CNS) are registered too rapidly to depend on nuclear, transcriptional mechanisms. Within the field of molecular endocrinology, interpretations of hormone action as being membrane initiated were often considered antithetical to interpretations relying on transcriptional facilitation. This chapter illustrates rapid actions of hormones in the CNS and shows how rapid, membrane-based effects can actually facilitate later genomic actions. Such data foster a unified view of steroid actions on neurons.