摘要: THE CONCEPT of chemical messengers or "hormones" was first recognized with the pioneering studies Bayliss and Starling 1 in 1902 when they showed that perfusion intestine acid resulted pancreatic secretion, injections crude extracts duodenal mucosa produced a similar stimulation pancreas. Classically, hormone has been defined as "any substance normally cells some part body carried by blood to distant parts, which it affects for good organism whole." With increasing recognition many hormones act locally well at sites, have operationally "chemical are dissolved extracellular fluid carry information between cells." 2 Recent suggested we may modify further our concept what is how reaches its