The “New Endocrinology”: Its Scope and Its Impact

An overview of the field of biology of chemical mediation is presented, emphasizing that “classical” endocrinology is a major and still vital segment of the field. The “new” endocrinology recognizes the importance of autocrine and paracrine mechanisms,the indistinct boundary between hormones and growth factors, and the existence of chemical mediation between organisms of the same and different species (pheromones and allelochemics). All these phenomena involve the same basic language: a specific agent activates a specific receptor, resulting in an action. The continuing need for organismal (integrative) endocrinology in interpreting and evaluating the contributions of molecular endocrinology is illustrated by a consideration of transgenic fish (bearing additional growth hormone genes) and of the presence of hormones in eggs and their implication for developmental biology