Cell surface receptors are multifunctional proteins with binding sites towards the external environment and effector sites which mediate intracellular events. The purpose of this symposium was to bring together investigators who have a com mon interest in those receptors which are located in the liver, and who have studied endocytic mechanisms for various macromolecules like insulin, lipoproteins, epi dermal growth factor and others. Experiments in this particular field of research date back to the early 60-ies but have only recently led to new and important in sight in the molecular basis of receptor mediated uptake in the liver. The structural features which control these mechanisms are currently under intense investigation in many laboratories. Though this symposium largely emphasizes lipoprotein up take and catabolism by the liver, it was the particular intention of the organizers to discuss methodology and results with investigators who are also interested in he patic uptake of macromolecules. This might then eventually lead to new and com mon concepts for both receptor-ligand interaction and internalization processes in the liver. Biochemists, pathologists and gastroenterologists met for two and a half days and discussed their latest data in this so rapidly developing field of basic rese arch. This conference is part of a series on current topics in gastroenterology and hepatology arranged regularly by the Departments of Medicine and Surgery at the University Hospital Eppendorf. If is our hope, that such exchange of information between the different disciplines in medicine will continue. i. k."