Endocrinology VI. [antikvár]

Preface The student of endocrinology always asks the question : why have two such dissimilar endocrine tissues come together in one organ, the adrenal gland? The distinction between the adrenal cortex and the adrenal medulla was recognized by the early anatomists, such as Caspar Bartholinus the Elder, who in 1611 described the adrenal gland as "capsulae atrabilariae", a capsule filled with black fluid. (This was a result of the rapid postmortem autolysis of the medulla.) Twenty years ago the editors of a volume like this would have been unable to add much more about the functional significance of the anatomic arrangement, except to point out that both parts of the adrenal gland are tissues that secrete their hormones in response to stressful conditions. Now there are, at last, clues that some of the functions of the medullary chromaffin cell are influenced by, and may even depend on, a continuous exposure to the very high concentrations of steroid hormones in adrenal venous blood. Perhaps, as our understanding increases of the funda- mental processes in the chromaffin cell and of the nature and control of secretions of adrenal steroids, we shall be able to provide a better answer to the student's question. For the time being, we hope that the reader will find in this volume much to compare and contrast between the two types of secretory tissue in the adrenal gland. Perhaps he will also be glad that, from time to time, the endocrinologist has to sit back from his research into the intricacies of hormones and reflect on the significance of his work for physiology. We hope that the material collected in this volume will not just be seen as a collection of essays but rather as a foundation upon which the physiologist can build a better understanding of the functions of the adrenal gland as a whole. As Volume Editors we are very aware of the painstaking work done by the authors in preparing their chapters and by the American Physiological Society editorial team of Kathleen K. Lamar and Elspeth M. Root. To all these we express our gratitude. HERMANN BLASCHKO A. DAVID SMITH GEORGE SAYERS Volume Editors