A Brief History of Modern Endocrinology and Definitions of a True Hormone

Background and Objective: An overview of the history of endocrinology indicates that definitions of some initially developed concepts, including the term ‘hormone’ have been changed over time. This review provides a historical overview of current definitions of ‘hormone’ and the criteria of a true hormone. In addition, a brief history of hormone-related concepts and their transformation over time are discussed. Results: Classically, a hormone is...