Physiological and Biochemical Adaptation During Development and Regression of Isoproterenol-Induced Cardiac Hypertrophy
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University of Windsor Scholarship at UWindsor Electronic Theses and Dissertations Theses, Dissertations, and Major Papers 1-1-1987 Physiological and biochemical adaptation during development and regression of isoproterenol-induced cardiac hypertrophy. Qian Tang University of Windsor Follow this and additional works at: https://scholar.uwindsor.ca/etd Recommended Citation Tang, Qian, "Physiological and biochemical adaptation during development and regression of isoproterenol-induced cardiac hypertrophy." (1987). Electronic Theses and Dissertations. 6147. https://scholar.uwindsor.ca/etd/6147 This online database contains the full-text of PhD dissertations and Masters’ theses of University of Windsor students from 1954 forward. These documents are made available for personal study and research purposes only, in accordance with the Canadian Copyright Act and the Creative Commons license—CC BY-NC-ND (Attribution, Non-Commercial, No Derivative Works). 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PHYSIOLOGICAL AND BIOCHEMICAL ADAPTATION DURING DEVELOPMENT AND REGRESSION OF ISOPROTERENOL-INDUCED CARDIAC HYPERTROPHY by Qian Tang A Dissertation submitted to the Faculty of Graduate Studies and Research through the Department of Biological Sciences in Partial Fulfillment of the requirement for the Degree of Doctor of Philosophy at the University of Windsor Windsor, Ontario, Canada 1987 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number: DC53244 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. UMI’ UMI Microform DC53244 Copyright 2009 by ProQuest LLC All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Qian Tang © 1987 All Rights Reserved 867022 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ABSTRACT PHYSIOLOGICAL AND BIOCHEMICAL ADAPTATION DURING DEVELOPMENT AND REGRESSION OF ISOPROTERENOL INDUCED CARDIAC HYPERTROPHY by Qian Tang Cardiac hypertrophy was induced in adult female Wistar rats (190-210 g> following daily subcutaneous injections of isoproterenol (ISO) (0.3 mg/kg body wt) for 12 days. A stable 44% tissue growth was achieved after 8 days with a half-time of 3.6 days. Ventricular RNA content was elevated 85% with a half-time response of approximate!y 2.0 days. Total hydroxyproline content remained stable during the first 2 days and increased 46% after 4 days of treat ment. Ventricular DNA content increased 19% after 8 days of therapy. Following 20 days of regression from estab lished hypertrophy (44%), cardiac mass and tissue RNA content did not completely regress to the control values. The half-time response for heart weight and tissue RNA was 3.8 and 3#4 days respectively. However, myocyte RNA was stimulated 86% and completely recovered after 12 days of regression. The elevated hydroxyproline and ventricular DNA content did not change during the 20 days of recovery. Muscle pump function (dP/dt max) was increased after 4 days of hypertrophic growth. Following regression, muscle contract!1ity remained elevated during the first 2 days but returned to control level following 4 days of recovery. iv Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Nuclear function in isolated myocyte and nonmyocyte nuclei was stimulated in a coordinated manner. RNA polymerase activity, chromatin template capacity in both myocyte and nonmyocyte nuclei were activated in the early stage (1-4 days) of hypertrophy. RNA polymerase binding to chromatin, in both myocyte and nonmyocyte fractions, was enhanced after 4 days of induced growth. In addition, RNA polyme rase activity, chromatin template function, and its binding capacity to RNA polymerase in myocyte nuclei, were all higher than the nonmyocyte nuclei indicating myocytes have higher transcritptional capacity than the nonmyocyte cells. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. DEDICATION To my homeland - CHINA V i Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ACKNOWLEDGEMENTS First of all, I would like to thank my wife Xiang and daughter Stephanie for their love, concern and full support given to me while I was conducting this investigation. I would also like to extend my appreciation to Dr. Paul B. Taylor, academic adviser and friend, for his guid ance, encouragement and support throughout my tenure at the University of Windsor. Sincere thanks are given to my doctorate committee members. Dr. David Cotter, Dr. Hugh Fackrel1, Dr. Keith Taylor and to my external examiner. Dr. BorivoJ Korecky. Their interest, invaluable input and friendship made my work on this project a real pleasure. To my good friend and partner, Mrs. Meg Jacobson, who unselfishly gave her assistance during this study, a special thanks is extended. Finally, 1 would like to express my sincere gratitude to the Government and the Embassy of the People"s Republic of China. Without their support, my study in Canada would not have been p o s s ib le . -, v i i Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS ABSTRACT.......................................................................................................................... iv DEDICATION..................................................................................................................... v i ACKNOWLEDGEMENTS........................................................................................................v i i LIST OF TABLES................................................................................. x LIST OF FIGURES........................................................................................................ x i i LIST OF ABBREVIATIONS.........................................................................................x i i i INTRODUCTION............................................................................................................... 1 METHODS An i mal s . .......................................... 11 Development of cardiac hypertrophy ............... 11 Regression of cardiac hypertrophy ............................... 11 Hemodynamic measurements. ....................... 12 Tissue RNA, DNA, protein and hydroxyproline assay... 13 Isolation of myocytes............................................................ 14 Extraction of myocyte nucleic acids. ............. 16 Isolation of myocyte and nonmyocyte n u c le i.......... 16 Preparation of chromatin .................................... 18 Determination of RNA polymerase activity .............................. 18 Measurement of total chromatin template activity.... 19 Conditions for RNA polymerase binding without reinitiation .................................................................................... 20 DNA fragmentation... ............... 22 Data analysis. ............... 23 CHAPTER 1. DEVELOPMENT OF ISOPROTERENOL-INDUCED CARDIAC HYPERTROPHY: BIOCHEMICAL STUDY Introduction......................... 25 R esults Body weight and heart w eig h t..... .................. 26 M yocardial RNA and D N A ............................. 26 Myocyte RNA. .................................. 33 Myocardial protein and hydroxyprol ine ....................... 33 Discussion...... ....................... 37 CHAPTER 2. REGRESSION OF ISOPROTERENOL-INDUCED CARDIAC HYPERTROPHY: BIOCHEMICAL STUDY I n troduc t i on . ............................................. 44 Resu1ts Body w eight and h e a rt w e ig h t ....................... 46 Myocardial protein and hydroxyprol ine ............................. 46 Myocardial RNA and DNA .......................................... 50 Myocyte RNA ............................. 52 Di scussi on............... 56 v i i i Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CHAPTER 3 . DEVELOPMENT AND REGRESSION OF ISOPRO TERENOL-INDUCED CARDIAC HYPERTROPHY: HEMODYNAMICS AND CONTRACTILE FUNCTION Introduction....................................................................................................