Receptor-Mediated Binding and Internalization of Toxins and Hormones presents the proceedings of a conference conducted for the purpose of exploring relationships between hormones and toxins, specifically, receptor-mediated internalization of toxins and hormones and the role of this internalization in message transmission and biodegradatory processes. This book is divided into three sections, with the first focusing on model systems of internalization. It presents pictorial illustrations of the receptor-mediated endocytosis of low-density lipoprotein via coated regions of membrane and discusses the receptor for lysosomal enzymes on the surface of cultured fibroblasts. The second section focuses on toxins and hormones and discusses such topics as receptor-mediated internalization of diphtheria toxin, diphtheria toxin interactions with an inhibitory activity from plasma membranes, and uptake mechanisms for ADP-ribosylating toxins. The third and final section focuses on hybrids and discusses such topics as chimeric toxins containing fragment A from diphtheria toxin, directed entry of hybrid proteins into cells via alternate receptors, and a hybrid protein of monoclonal anti-THY 1.2 and diphtheria toxin fragment A. This book will be of interest to practitioners in the fields of endocrinology, cell biology, and molecular genetics.