Cailin Chen Docteur en Médecine Hunan Medical University CONTROL OF THE FORMATION AND THE ACTION OF ANDROGENS IN PERIPHERAI, TISSUES These présentée B la Faculté des études supérieures de 11Universit4Laval pour l'obtention du grade de Philosophiae Doctor (PhD.) Départment de Physiologie (Endocrinologie moléculaire) FACULTÉ DE MÉDECINE UNIVERSITÉ LAVAL QUÉBEC MAI 1996 8 Cailin Chen, 1996 Biblioth ue naaionale du Cana"ei a Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 395 Wellington Street 395. me Wellington MEawaON KlA ON4 OrtewaOkl KtAON4 Caneda Canada The author has granted a non- L'auteur a accordé une licence non exclusive licence ailowing the exclusive permettant a la National Library of Canada to Bibhotheque nationale du Canada de reproduce, loan, distn'bute or seii reproduire, prêter, distribuer ou copies of this thesis in microfonn, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfiche/fdm, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fiom it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. To: Xun, Chenchen, and My parents L'andtoghe actif 5a-dihydrotestost6rone (Dm joue un r61e prédominant tan physiologique important dans la peau et la prostate. Afin de mieux comprendrd les mécanismes impliqués dans la formation et l'action de la Dïïï, nous avon 4tu&4 la distribution tissulaire de certaines enzymes de la stéroïdogénèse chez 1r hamster et nous avons démontré la psesence des enzymes nécessaires h li biosynthbe de la DHT dans tous les tissus stdroidogéniques et une series dr tissus périphériques. De plus, nous avons dtudié les effets des précurseur: surrénaliens dehydroépiandrostérone (DHEA)et androsténédione (~4-dione administrés de faqon percutanée et systémique sur les param&tresandrogéno sensibles chez le hamster et nous avons démontré l'effet androgéniquc systémique de ces précurseurs surrénaliens. Enfin, dans le but d'améliore] l'efficacité de traitement des maladies androgéno-sensibles, nous avons vérifié li capacite de certains antiandrogénes et inhibiteurs de la Soc -réductase B bloquer 1; formation et l'action des androghes, et ce, chez le hamster ainsi que chez li souris porteuse de carcinomes mammaires Shionogi androgéno-sensibles. Fernand Labrie, Director LONG SUMMARY It is well recognized that in the human and other primates, androgens are synthesized from both the testicular and adrenal origins. The intracellula! formation of the active androgen Sa-dihyotestosterone (Dm) from the inactive adrem1 steroid precursor dehydroepiandrosterone sulfate (DHEAS) involves four enzymes; namely steroid sulfatase, 3 p-hydrox ys ter oid dehydrogenase/b4-ASisomerase (3$-HSD), 17&hydroxysteroid dehydrogenase (17p-HSD) and Sa-reductase. In order to better understand the rnechanisms involved in the steroidogenic process, we have studied the tissue distribution of the enzymatic activity of the abovementioned steroidogenic enzymes required for the synthesis of active androgens in both male and female hamsters. The activities of steroid sulfatase, 3$-HSD, 17p-HSD, and Sa-reductase were measured in al1 of the 14 tissues examined. We have also investigated the effects the adrenal precursors DHEA and d-dione administered systemically oz percutaneously by comparing their effects with those of the active androgens testosterone (T) and DHT in the orchiectomized hamster. We have demonstrated that al1 the compounds stimulated the size of flank organs, the size of the underlying sebaceous glands, and the weight of the prostate. However, their stimulatory potency is in deaeasing order starting with DHT, T, h4-diane, and DHEA, respectively. These results suggest that DHEA and a4- dione cm be transformed into active androgens in peripheral tissues in the hamster. In condusion, the steroidogenic enzymes, namely steroid sulfatase, 3& HSD, 17p-HSD, and Sa-reductase, which are required for the formation of active androgens, are present not only in the classical endocrine tissues such as the gonads and adrenals, but also in a series of peripheral intracrine tissues in the hamster. Therefore, the hamster provides a good animal model to investigate control of the formation and action of androgens in peripheral tissues. Using the same animal model, we then investigated the antiandrogenic effects of the non-steroidal antiandrogen flutamide as well as the Sa-reductase inhibitor finasteride in male hamsters. These compounds were applied topically on the right flank organ and right ear. A four-week treatment decreased the size of the flank organ on both sides, as weli as the weights of the prostates and seminal vesicles, thus indicating that both flutamide and finasteride exert tbir effects systemical)y. Moreover#we have examinecl the antiandrogenic effects of a series of steroidal compounds synthesized in our medieinal chemistry division Arnong them, EM-250 (17p-alkynyl substituted testosterone derivative) wa! found to be a pure topical antiandrogen while EM-402, one of 17B-(N. alkylformamido)-substituted 4-methyl-4-azasteroids, was fond to be a poten topical Sa-reductase inhibitor. Furthermore, we have studied the responsiveness of the growth of thc androgen-sensitive Shionogi tumor to androgen deprivation. In thi! experiment, we observeci that small tumors were highly sensitive to androger deprivation, while loss of responsiveness developed with increasing tumor size This indicates that, for optimal efficacy in the treatment of prostate cancer androgen blockade should be given at the early stage when the tumor has i small volume and is still organ-confined. Finally, we have investigated thi inhibitory effect of treatment with flutamide and finasteride, or with i combination of both compounds, on Shionogi tumor and prostate growth ii mice. Our data have demonstrated that an additive inhibitory effect can bc achieved with the combination treatment. These data suggest that sud combination therapy could be beneficial in the treatment of androgen-sensitivc diseases where optimal inhibition of DHT formation and action is desired. PREFACE Although my graduate studies took a relatively short peroid of my life, the thought of ending this special and important stage is difficult. During my graduate studies, 1 acquired the ability to carry out independent research in the fields of EndOCIiI\C)Iogy and Phatmacology. This has been made possible through the generous help and guidance of my supervisor and colieagues. 1 shall never forget the people with whom 1 worked nor their cooperation and help during my study at the Research Center of Molecular Endocrinology at Laval University. First, 1 wodd iike to express my deep gratitude and appreciation to my supervisor, Dr. Femand Labrie, for his expertise, time, patience and guidance throughout my Ph.D. training. With Dr. Labrie's personal instructions and support, I was able to step on the scientific research podium and accomplish my PhD. study . 1 am greatiy indebted to my jury members: Dr. Leone110 Cusan, Rudi Neri, Roland Tremblay and othet professors: Alain Belanger, Van Luu-The, Claude Labrie, Georges Pelletier, Richard Pouiin, and Jacques Simard for giving me the support and advice to enable me to complete this thesis. Acknowledgments must also be given to al1 the In Vivo Study group (in alphabetical order): Drs. Jacques Couët, Michel Flamand, Jim Gourdon, Shengrnin Li, Ceiine Martel, Claude Trudel, Messieurs Yvan Labrie, Shouqi Luo, Andr4 Petitderc, Michel Rouleau, Alain St-Pierre, Milos Stojanovic, Mesdames Gina Gravel, Nancy Lemieux, France Létourneau, and Antigone Sourla for their ftiendly help and collaboration. 1 thank the Chemistry group for their timely provision of the compounds 1 studied, especially Drs. Shankar M Singh, and Yves Merand. 1 also thank Mesdames Louise Desy, France Lepire, Jacynthe Malenfant, Johanne Ouellet, Dr. Jean Côte, Messieurs Simon Caron, Roger Lachance, adGüles Leblanc for their skilled technical assistance. 1 would iike to thank othet graduate students, postdoctoral students and coîieagues, for thw cheerfui companionship and coilaboration in the laboratory. 1 appreciate the dynamism and quality of the work of Dr. Gilles Charpene Mesdames Aline Douville, Louise Doyon, Joyce Gardiner, Eiaine Leclerg José Pouiin, H4lène Rodrigue, Lise Thériault, and Marléne Walsh. 1 would like t thank the group of Medical Iiiustration and Photography for their quality an efficient work: Mesdames Anne Borgeat, Kathleen BUand Sylvia Kursteine: Messieurs Gilles Chabot, Marc Auger and Bertrand Vaillancourt. 1 also than Madame Carde Brault for her assistance in searching the iiteratures. Finally, 1 wish to express my gratitude to my family, Dad, Mom, sisters, anl brothers for their never ending love and support through al1 these years c sdiool. 1 would iike to give my special thanks to Xun, my husband and my bei friend, for always being there; and to my precious littie boy Chenchen who is m inspiration to finish writing this thesis. TABLE OF CONTENTS RÉSUMÉ COURT .................................................................................................................. LONG SUMMARY ...................................... +..:.................................................................