Preface This third 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 mostly based on comments and questions received from medical students. In addition, the test questions at the end of the chapter have been modified to reflect clinical scenarios that require the integration of the endocrine physiology concepts presented in the respective chapter. New figures have been added 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