Introduction

Abstract

Part V attempts to provide a comprehensive overview of the structure and function of the gastroenteropancreatic (GEP) hormone system in submammalian vertebrates. This system is responsible for regulating and coordinating the functions of the gastrointestinal tract and for the appropriate distribution of the products of digestion as well as the maintenance of appropriate levels of circulating metabolites essential for cellular metabolic activities. The origin, structure, and functions of the various hormones in the vertebrates are presented, and, where appropriate, the GEP hormone activities are integrated with the hormonal background provided by other essential hormones, such as the thyroid, adrenocortical, and adrenomedullary secretions. It is hoped that evolutionary trends in the regulation of the processing and distribution of a nutrient load can be identified and brought together in a cohesive structure. In this undertaking there are excellent reviews which serve as important sources and entry points into the original literature. A few of the more recent papers have been listed in the selected readings section at the end of Chapter 18.