In the beginning of this century physiology witnessed the creation of a new concept, the hormonal regulation of the work of the digestive organs. It was found that such essential functions as the flow of pancreatic juice and emptying of bile into the intestine were regulated by two hormones, secretin and cholecystokinin, respectively. Already in 1925 French authors attempted to measure the functional capacity of the exocrine pancreas by means of stimulation with secretin. The use fulness of the secretin test in this connection was definitely established by Scandinavian workers in the 1930's. In spite of the difficulties in obtaining secretin American authors succeeded in keeping the interest in the secretin test alive. The development in the 1950's of counter-current, ion exchange and chromato graphic techniques offered new possibilities in this field. The intestinal hormones were known to be relatively low molecular peptides and these could now be isolated in pure form. Thus secretin was isolated in 1961, and cholecystokinin in 1964. The newly developed methods for peptide analysis likewise soon brought us full information about the primary structure of the peptides. Gastrin, the specific stimulant of the gastric acid secretion, which was discovered in 1905 and acknowledged as a hormone in 1938, was the first of the gastrointestinal hormones for which the structure became known. This was in 1964. Synthesis soon followed. These developments are reviewed in the first chapter of the present volume.

Inhalt
I Secretin and Cholecystokinin (CCK). With 42 Figures.- A. Secretin.- B. Common Aspects on the Gastrointestinal Hormones.- C. Biological Actions of the Gastrointestinal Hormones.- D. The Bioassay of Secretin and Cholecystokinin.- References.- II The Synthesis of (Porcine) Secretin. With 6 Figures.- A. Introduction.- B. Strategies.- C. Attempted Synthesis of Secretin on a Solid Support.- D. Synthesis of Secretin by the Stepwise Approach (Through Isolated Intermediates).- E. Synthesis of Secretin by Fragment Condensation.- F. The Conformation of Secretin.- G. Conclusions.- References.- III The Secretory Process in the Pancreatic Exocrine Cell: Morphologic and Biochemical Aspects. With 16 Figures.- A. Route and Timetable of Intracellular Transport in Resting Exocrine Cells.- B. Metabolic Requirements for Intracellular Transport over the RER-Condensing Vacuole-Pathway (steps 24).- C. Metabolic Aspects of Condensing Vacuole Transformation.- D. Studies on Zymogen Granule Discharge.- E. Metabolic Requirements for Zymogen Granule Discharge.- References.- IV The Secretin Test. With 7 Figures.- A. General Introduction.- B. The Secretin Test of Pancreatic Function.- C. Secretin-Pancreozymin Tests of Pancreatic Function.- D. Serum Enzyme Tests in the Diagnosis of Pancreatic Disease.- References.- V On the Use of Cholecystokinin in the Roentgenological Examination of the Extrahepatic Biliary Tract and Intestines. With 17 Figures.- 1. Gall Bladder and Cholecysto-Cystic Junction.- 2. Sphincter of Oddi.- 3. Intestines.- References.- VI Gastrointestinal Hormones and Islet Function. With 37 Figures.- I. Introduction.- II. Historical Review.- III. Some Remarks on the Chemical Structure, Extra-insular Actions and Sites of Origin of the Gastrointestinal Hormones.- IV. ThePharmaco-Chemical (or Pharmaeo-Dynamie) Approach to the Intestinal Factor in Question.- V. Reaction of the Intestinal Hormones in Response to Ingestion of Food.- VI. Chemical Configuration and Endocrine Action of the Intestinal Hormones. The Role of the Exocrine Pancreas in the Regulation of Islet Function by Intestinal Hormones.- VII. Reestablishment of the Primary Role of Non-Physiological Glucose Levels in Regulating Insulin and Glucagon Secretion, Irrespective of Cholecystokinin-Pancreozymin and Secretin Action.- VIII. The Significance of Intestinal Modulation of Islet Function.- IX. Summary and Conclusions.- References.- VII The Use of Cholecystokinin in the Roentgenological Examination. Clinical Aspects. With 10 Figures.- I. Introduction. Early History.- II. Cholecystokinin and the Evacuation of the Gallbladder.- III. Cholecystokinin and the Common Bile Duct.- IV. Cholecystokinin, the Sphincter of Oddi and Duodenal Motility.- Cholecystokinin and the Postoperative Choledochus.- V. The Use of Cholecystokinin in Endoscopy.- VI. Cholecystokinin in the Scintigraphy of the Gallbladder and Pancreas.- VII. Cholecystokinin and Duodenal and Ileal Peristalsis.- VIII. Conclusions.- References.- Author Index.