Preface

This fifth edition of Endocrine Physiology provides comprehensive coverage of the fundamental concepts of hormone biological action. The content has been revised and edited to enhance clarity and understanding, and illustrations have been added and annotated to highlight the principal concepts in each chapter. In addition, the answers to the test questions at the end of the chapter have been expanded to include explanations for the correct answers. Figures have been added and others have been revised to enhance the understanding of important endocrine physiology concepts.

The concepts herein provide the basis by which first and second year medical students will better grasp the physiologic mechanisms involved in neuroendocrine regulation of organ function. The information presented is also meant to serve as a reference for residents and fellows. The objectives listed at the beginning of each chapter follow those established and continually updated by the American Physiological Society for each hormone system and are the topics tested in Step I of the United States Medical Licensing Exam (USMLE).

As with any discipline in science and medicine, our understanding of endocrine molecular physiology has changed and continues to evolve to encompass neural, immune, and metabolic regulation and interaction. The suggested readings have been updated to provide guidance for more in-depth understanding of the concepts presented. They are by no means all inclusive, but were found by the author to be of great help in putting the information together.

The first chapter describes the organization of the endocrine system, as well as general concepts of hormone production and release, transport and metabolic fate, and cellular mechanisms of action. Chapters 2–9 discuss specific endocrine systems and describe the specific hormone produced by each system in the context of the regulation of its production and release, the target physiologic actions, and the clinical implications of either its excess or deficiency. Each chapter starts with a short description of the functional anatomy of the organ, highlighting important features pertaining to circulation, location, or cellular composition that have a direct impact on its endocrine function. Understanding the mechanisms underlying normal endocrine physiology is essential in order to understand the transition from health to disease and the rationale involved in pharmacological, surgical, or genetic interventions. Thus, the salient features involved in determination of abnormal hormone production, regulation, or function are also described. Each chapter includes simple diagrams illustrating some of the key concepts presented and concludes with sample questions designed to test the overall assimilation of the information given. The key concepts provided in each chapter correspond to the particular section of the chapter that describes them. Chapter 10 illustrates how the individual endocrine systems described throughout the book dynamically interact in maintaining homeostasis.

As with the previous editions of this book, the modifications are driven by the questions raised by my students during lecture or when studying for an exam. Those questions have been the best way of gauging the clarity of the writing and they have also alerted me when unnecessary description complicated or obscured the understanding of a basic concept. Improved learning and understanding of the concepts by our students continues to be my inspiration. This has been further enhanced through my involvement in the Disease and Therapy of the Endocrine and Reproductive System course for our L2 medical students. Assessment of student knowledge of basic physiological principles and identification of challenging areas inspired several of the edits and amendments to this edition. I am grateful for both basic scientists and colleagues for their dedication to the teaching of this discipline and for enriching my understanding of what is critical knowledge for beginning medical students.