The Pennsylvania State University the Graduate School College of Health and Human Development
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The Pennsylvania State University The Graduate School College of Health and Human Development A FUNCTIONAL ASSESSMENT OF SALIVARY DEHYDROEPIANDROSTERONE SULFATE (DHEA-S) IN RESPONSE TO ACUTE STRESS A Dissertation in Biobehavioral Health by Courtney Allison Whetzel ©2008 Courtney Allison Whetzel Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy August 2008 ii The dissertation of Courtney Allison Whetzel was reviewed and approved* by the following: Laura Cousino Klein Associate Professor of Biobehavioral Health Dissertation Advisor Chair of Committee Sonia A. Cavigelli Assistant Professor of Biobehavioral Health Elizabeth J. Susman Jean Phillips Shibley Professor of Biobehavioral Health David M. Almeida Professor Human Development and Family Studies Collins O. Airhihenbuwa Professor of Biobehavioral Health, Head, Department of Biobehavioral Health *Signatures are on file in the Graduate School. iii ABSTRACT Dehydroepiandrosterone sulfate (DHEA-S) is one of the most widely circulating hormones in the body, and adult men have higher DHEA-S levels compared to adult women. Due to its unique lifetime rhythm (i.e., levels rise at 6-8 yrs, peak at 20-30 yrs, decline until death) and purported protective role in the health effects of aging (e.g., cardiovascular disease, dementia), DHEA-S has been studied as an anti-aging hormone. The antiglucocorticoid properties of DHEA-S suggest that it may protect against the long-term health consequences of chronic, stress-induced cortisol release. Little is known about the role of DHEA-S in the biological stress response in humans, but a handful of studies suggest that DHEA-S levels increase following intense physical stressors. This dissertation consists of 3 studies designed to investigate DHEA-S responses to acute laboratory stress in healthy adults. The first study was designed to 1) validate DHEA-S levels in saliva collected by Salivette® vs passive drool, 2) confirm sex differences in DHEA-S levels and 3) compare morning and late afternoon DHEA-S levels. Results validate salivary DHEA-S levels collected via Salivette® and confirm that men have higher levels of DHEA-S than do women. Further, DHEA-S levels are higher in the morning than in the late afternoon, which has not been reported before. The second and third studies measured DHEA-S levels in response to acute laboratory stressors. Study 2 compared salivary and serum DHEA-S across 3 time points (baseline, stress, recovery) in men and women in the luteal and follicular phases of the menstrual cycle. Results indicate that stress reduces DHEA-S levels, and that DHEA-S levels among women in the luteal phase rise above baseline levels during recovery. Study 3 expanded these results by measuring salivary DHEA-S levels following a math stressor in men given 1 of 3 different doses of a iv known sympathomimetic, caffeine (i.e., 0, 200, or 400 mg). Results confirmed the Study 2 findings and indicate that stress, but not caffeine, reduce DHEA-S levels among men. This dissertation ends with a discussion of the health implications of stress-induced changes in DHEA-S, how these changes relate to cortisol and recommendations for future studies. v TABLE OF CONTENTS LIST OF TABLES……………………………………………………………….…….x LIST OF FIGURES…………………………………………………………………....xi ACKNOWLEDGEMENTS……………………………………………………….......xiv CHAPTER I: INTRODUCTION…………………………………………….….…....1 Stress System Overview……………………………………………….……...3 Dehydroepiandrosterone (DHEA) and Dehydroepiandrosterone-Sulfate (DHEA-S)………………………………… 7 The Biology and Mechanism of Action of DHEA/S………………… 8 Lifetime Rhythm of DHEA/S………………………………………... 9 DHEA/S as a Neurosteroid and a Neuroactive Steroid………….….. 10 DHEA/S and Stress…………………………………………….……. 11 References……………………………………………………………….…... 15 CHAPTER II: VALIDITY OF MEASURING DHEA-S IN A COTTON SALIVETTE: A METHODOLOGICAL APPROACH TO DETERMINE SEX AND TIME OF DAY DIFFERENCES…….…. 19 Introduction………………………………………………………………...… 20 Study 1….……………………………………………………………….…... 22 Methods……………………………………………………………..... 22 Assay Procedure…………………………………………………...…. 23 Statistical Analyses……………………………………………….….. 23 Results ……………………………………………………………..… 24 Study 1 Conclusion…………………………………………………... 27 Study 2 ………………………………..……………………………………... 27 vi Methods………………………………………………………………. 27 Assay Procedure ……………………………………………………... 28 Statistical Analyses …………………………………………………... 28 Results……………………………………………………………..….. 29 Study 2 Conclusion...…………………………………………………. 33 General Conclusion……………………….………………………………….. .33 References…………………………………………………………………….. 37 Author Note…………………………………………………………………... 39 CHAPTER III: DHEA-S RESPONSE TO A LABORATORY STRESSOR IN MEN AND IN WOMEN IN DIFFERENT PHASES OF THE MENSTRUAL CYCLE ……………………… …………..……….. 40 Introduction………………………………………………………………..….. 41 Methods…………………………………………………………………..…… 43 Participants……………………………………………………….….... 43 Experimental Design…………………………………………….….… 45 Blood and Saliva Sample Handling ………………………………..…. 46 Assay Procedure for Saliva Samples.……………………………..…... 47 Assay Procedure for Serum Samples.……………………………..…... 47 Blood Pressure Determination ………………………………….….…. 48 Statistical Analyses………………………………………………..…... 48 Results……………………………………………………………………..…... 49 Stressor Confirmation ……………………………………………..…. 49 Systolic Blood Pressure………………………………….…..... 49 Diastolic Blood Pressure…………………………………...….. 49 vii Heart Rate……………………………………………………. 49 Self-Reported Stress…………………………………………. 50 Neuroendocrine Markers…………………………………………….. 50 Serum/Saliva Correlations for Cortisol .…………………….. 50 Salivary Cortisol ……………………...……………………... 50 Serum Cortisol …...………………………………………….. 51 Serum/saliva correlations for DHEA-S ……………………... 51 Salivary DHEA-S……………………………………………. 51 Serum DHEA-S……………………………………………… 52 Salivary DHEA-S/Cortisol Ratio..…………………………... 52 Serum DHEA-S/Cortisol Ratio..…………………………….. 52 Discussion……………………………………………………………………. 66 References…………………………………………………………….…….... 72 Author Note………………………………………………………….……….. 76 CHAPTER IV: DHEA-S RESPONSE TO AN ACUTE PSYCHOLOGICAL AND PHARMACOLOGICAL STRESSOR IN HEALTHY YOUNG MEN …………………………..….….…. 77 Introduction……………………………………………………………….….. 78 Methods……………………………………………………………………… 80 Experimental Design……………………………………………….… 81 Laboratory Protocol………………………………………………….. 82 Salivary Hormone Assessment………………………………………. 85 Salivary Cortisol……………………………………………... 85 Salivary DHEA-S……………………………………………. 85 viii Salivary DHEA-S/Cortisol Ratio…………………………….. 85 Statistical Analyses…………………………………………………... 86 Blood Pressure Determination……………………………………...... 87 Results………………………………………………………………………... 87 Stressor Confirmation………………………………………………... 87 Self-Reported Stress..………………………………………… 87 Self-Reported Nervousness..…………………………………. 87 Cardiovascular Measures…………………………………………….. 87 Systolic Blood Pressure……………………………………… 87 Diastolic Blood Pressure……………………………………... 88 Heart Rate………………………………………………....….. 88 Salivary Neuroendocrine Markers……………………………………. 88 DHEA-S………………………………………………….….... 88 Cortisol………………………………………………….…….. 88 DHEA-S/Cortisol Ratio…………………………………..….... 88 Discussion……………………………………………………………………. 100 References………………………………………………………………….… 103 Author Note………………………………………………………………….. 106 CHAPTER V: DISCUSSION…………………………………..………………...…. 107 Dissertation Aims………………………………………………………….… 108 Contribution to Literature………………………………………………….… 110 Findings Contrary to Literature…………………………………………….... 110 ix Associations Between Cortisol and DHEA-S and the Molar Ratio…………. 112 Neurosteroid vs. Peripheral Function of DHEA-S…………………………... 116 Testosterone and Other Sex Steroids………………………………………… 117 Allostatic Load Interpretation/Caffeine and Cardiovascular Disease Risk..… 119 DHEA-S Recommendations and Future Directions…………………………. 120 References……………………………………………………………………. 122 APPENDIX A. Salivary DHEA-S EIA Package Insert (DSL, Inc.)…………..…….. 126 APPENDIX B. Telephone Health History Questionnaire 1..………………………... 137 APPENDIX C. Progesterone EIA Package Insert (DSL, Inc.)………………………. 146 APPENDIX D. 17-β Estradiol EIA Package Insert (DSL, Inc.)……………………... 156 APPENDIX E. Salivary Cortisol EIA Package Insert (DSL, Inc.)..………….……… 167 APPENDIX F. Serum DHEA-S EIA Package insert (ALPCO Diagnostics)..…..…... 179 APPENDIX G. Serum Cortisol EIA Package Insert (DSL, Inc.)……………….…..... 186 APPENDIX H. Mood Assessment Scale…………………………………….….……. 196 APPENDIX I. Perceived Stress Scale……………………………………………….. 198 APPENDIX J. Telephone Health History Questionnaire 2..………………….……..... 200 APPENDIX K. Salivary Cortisol EIA Package Insert (Salimetrics, LLC)…….……... 209 x LIST OF TABLES Table 1. Age and body mass index (BMI; kg/m2) among men and women in the luteal and follicular phase of the menstrual cycle (means ± SEM)….. 54 Table 2. Experimental timeline ………………………………………..…………….. 55 Table 3. Age and body mass indices (BMI; kg/m2) of men administered no caffeine, 200 mg caffeine or 400 mg caffeine (means + SEM) ………... 90 Table 4. Experimental timeline ……………………………………………….……... 91 xi LIST OF FIGURES Figure 1. Steroid metabolic pathway: From cholesterol to DHEA and DHEA-S…………………………………………………………..…..…. 14 Figure 2. Average DHEA-S levels (ng/mL) (± SEM) collected by passive drool and Salivette® in male and female participants..………………….. 25 Figure 3. Average DHEA-S levels (ng/mL) (± SEM) collected by passive drool and Salivette® in men collected in the morning (panel A) and in the late afternoon (panel B) and in women collected in the morning (panel C) and in the late afternoon (panel D).…………………………………......... 26 Figure 4. Average salivary DHEA-S levels (ng/mL) (± SEM)