ABSTRACT

This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book describes the energetic requirements of the various steps in agonist-induced secretion processes. It introduces the thermodynamic aspects of energy producing, consuming sequences in the cell, and discusses the synthesis and storage of secretable products. The process of liberating granule material into the extracellular space is presented separately paying special attention to chemiosmotic processes, membrane fusion, and contractile mechanisms. The book discusses the alterations in energy producing and consuming pathways and changes in the concentration of adenosine triphosphate (ATP) which form the basis for a technique for the quantitative assessment of the energy requirements of secretion responses. Starting from the early work on ATP resynthesizing pathways and the identification of flux-controlling mechanisms, the concepts of phosphate potential and adenylate energy charge have emerged as central dominators in the regulation of supply and demand of metabolic energy.