Cognition and Steroidogenesis in the Rhesus Macaque Krystina G Sorwell A DISSERTATION Presented to the Department of Behavioral Neuroscience and the Oregon Health & Science University School of Medicine in partial fulfillment of the requirements for the degree of Doctor of Philosophy November 2013 School of Medicine Oregon Health & Science University CERTIFICATE OF APPROVAL This is to certify that the PhD dissertation of Krystina Gerette Sorwell has been approved Henryk Urbanski Mentor/Advisor Steven Kohama Member Kathleen Grant Member Cynthia Bethea Member Deb Finn Member 1 For Lily 2 TABLE OF CONTENTS Acknowledgments ......................................................................................................................................................... 4 List of Figures and Tables ............................................................................................................................................. 7 List of Abbreviations ................................................................................................................................................... 10 Abstract........................................................................................................................................................................ 13 Introduction ................................................................................................................................................................. 15 Part A: Central steroidogenesis and cognition ............................................................................................................. 34 Chapter 1: Steroidogenic potential of the rhesus macaque brain ................................................................................ 35 Chapter 2: Effects of the precursor hormone dehydroepiandrosterone on cognition in pre- and perimenopausal rhesus macaques .......................................................................................................................................................... 45 Chapter 3: Changes in central steroidogenic enzymes with age and mechanisms for the inefficacy of DHEA supplementation in humans and nonhuman primates. ................................................................................................. 66 Part A Summary: The cognitive benefits of hormone therapy in the female are complicated by multi-level systems interactions .................................................................................................................................................................. 77 Part B: Role of endocrine interactions in cognition ..................................................................................................... 78 Chapter 4: Central and peripheral endocrine interactions in models of female hormone therapy ............................... 79 Chapter 5: Adrenal interactions in male rhesus macaque ............................................................................................ 92 Chapter 6: Sex differences in endocrine interactions................................................................................................. 102 Part B Summary: Endocrinology as a whole-body integrator of aging physiology ................................................... 109 General Conclusion ................................................................................................................................................... 110 Appendix A: RT-PCR and qRT-PCR primers and probes ........................................................................................ 113 Appendix B: References ............................................................................................................................................ 119 3 Acknowledgments It is hard to see only one name on the title page of this dissertation. None of the work I have completed while at Oregon Health & Science University was performed in a vacuum, and nothing would have been achieved without the generous support and collaboration of my colleagues, mentors, and friends during this time. First and foremost, Dr. Henryk Urbanski has been instrumental in guiding me through the trials and tribulations of primate research, graciously providing me with countless leads on new directions for my work to take. He has been willing to listen to all of my crazy ideas and proposals over the years, some of which even worked out once in a while. Dr. Steve Kohama has become my first resource for answering seemingly out-of-nowhere questions, and has provided me with staggering amounts of expertise in nearly every laboratory technique I have attempted. I sincerely thank the members of my dissertation committee, Dr. Urbanski, Dr. Kohama, Dr. Kathy Grant, and Dr. Cynthia Bethea, for their willingness to guide me to this point over the last few years. Their understanding of the difficulties of research has wisely talked me down from my over-exuberance for answering every little question, and they have given me wonderfully useful perspectives for the importance of my work. The behavioral work I have chronicled here could not have been completed without the laboratory of Dr. Martha Neuringer, and I especially owe a genuine thanks to Laurie Renner for the miraculous level of data organization that made my analyses infinitely less time-consuming. Collection of cognitive data was not possible without the help of Alison Weiss, Jamie Garten, and Noelle Landauer. Perhaps the most important members of Dr. Neuringer’s lab, however, 4 have been the monkeys. These animals have been remarkable not only as research subjects, but as fellow beings. Their sacrifice is greatly appreciated. For his instructional and supportive contributions to this dissertation, I thank graphic design extraordinaire Jeff Hayes. Even in the final hours of panic in completing this work, he was able to patiently teach me how to make a figure look decent, simple, and communicative. The faculty and administrative staff at both OHSU and ONPRC have been instrumental in both support and working out all the little details to make my experience here as smooth as possible. Dr. Suzanne Mitchell has been immensely helpful in her role as Program Director. Kris Thomason and Nicole Ernst in the Department of Behavioral Neuroscience, and Louise Sacha and Travis Dewey at the ONPRC have always miraculously known the answer to any question posed to them, and have always gone out of their ways to solve any administrative issues I have encountered. Upon moving across the country, thousands of miles from any family, I made myself a new one. Anna and Lily have been at my side through every step of graduate school, from the first day to the last. While they may have no idea what happens when I walk out the door every morning, they know that when I come home every night all I need is a cat or two on my lap to make it a good day. The work presented in this dissertation covers the learning and preparation I have completed over the last six years in the Department of Behavioral Neuroscience. I have devoted over one hundred and sixty pages to this time in my life, and while this has been a truly formative process, I find it difficult to devote a scant page or two to acknowledge the learning, experiences, and support that initially brought me to graduate school. I could have attended any graduate school, studied any biological system, succeeded under any mentor, but I never would 5 have developed the passion for science and learning that brought me here without the help of many people over the years. For cultivating my love of puzzles from before I could even read, I thank my family. For showing me that science, instead of being a rule that exists in text books, is just a series of puzzles picked apart by real people living real lives, I thank my high school Biology teacher Miss Jenny Wolf. She showed me that there was no reason I could not be one of those solvers of puzzles, instead of just an observer, and simply by taking a sincere interest in my future was able to set me on the trajectory to follow a passion I didn’t even know I had. And finally, for showing me that the brain is the ultimate of all puzzles, I thank my undergraduate professional mentor, Dr. Michael Baum, and my personal mentor, Dr. Daniel Wesson. They were the first to convince me that someday I too could have those three sacred letters after my name, and I know they would be proud to know that I am almost there. This work was supported by the following grants from the National Institutes of Health: AG-023477 HD-007133 OD-011092 AG-029612 HD-029186 RR-000163 AG-036670 HD-018185 6 List of Figures and Tables Figures Introduction I.1 Aging demographics in the United States from 1950 projected to 2050 I.2 Female and male hypothalamic-pituitary-gonadal axes I.3 Hypothalamic-pituitary-adrenal axis I.4 Hormone synthesis pathway: synthesis of testosterone, estradiol, and cortisol from cholesterol I.5 Delayed response performance in aged female rhesus macaques treated with estradiol or estradiol plus progesterone Chapter 1 1.1 Expression of steroidogenic enzyme mRNA in multiple areas of the rhesus macaque brain 1.2 Expression of steroidogenic proteins in the rhesus macaque hippocampus Chapter 2 2.1 Experimental timeline of training, testing, and DHEA supplementation 2.2 Examples of trials in delayed match-to-sample and delayed response touchscreen tasks 2.4 Representative menstrual cycles of regularly- and irregularly-cycling aged female rhesus macaques