Steroid Biochemistry Volume II Editor Ronald Hobkirk, Ph.D., D. Sc. Professor of Biochemistry University of Western Ontario London, Ontario, Canada Boca Raton London New York CRC PressC isR anC im Pprrinets osf, thIenc. Taylor B&o Fcraanc Ris Gartoounp,, a nF ilnoforrimdaa business First published 1979 by CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 Reissued 2018 by CRC Press © 1979 by CRC Press, Inc. CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. 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CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Library of Congress Cataloging in Publication Data Main entry under title: Steroid biochemistry. Includes index. 1. Steroid hormone metabolism. 2. Biological chemistry. I. Hobkirk, Ronald, 1930- [DNLM: 1. Steroids — Biosynthesis. 2. Steroids — Metabolism. QU85 S8355] QP572.S7S73 599’ .01’9243 79-11988 ISBN 0-8493-5193-6 (v. 1) ISBN 0-8493-5194-4 (v. 2) A Library of Congress record exists under LC control number: 79011988 Publisher’s Note The publisher has gone to great lengths to ensure the quality of this reprint but points out that some imperfections in the original copies may be apparent. Disclaimer The publisher has made every effort to trace copyright holders and welcomes correspondence from those they have been unable to contact. ISBN 13: 978-1-315-89781-3 (hbk) ISBN 13: 978-1-351-07691-3 (ebk) Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com PREFACE It was initially anticipated that about eight or nine chapters on various topics in steroid biochemistry would constitute a single volume of this publication. However, it became apparent that the literature in certain of the areas covered was so considerable as to necessitate two volumes, each containing four chapters. Since it was clearly ad- vantageous that these volumes should be of approximately equal length, the original order of chapters had to be altered somewhat. This change, however, has not resulted in any major disadvantage. An attempt has been made to attract contributions which illustrate the importance of certain enzymatic processes involved in steroid biosynthesis and metabolism and, in some cases, leading to steroidal action in target sites. Investigators actively engaged in research in such areas were invited to present their material in a manner which they considered fitting. It is hoped that as a result of this, the publication will possess suf- ficient depth to warrant approval. The blend of review material and experimental data originating in the authors' laboratories will, it is felt, make for useful reading. As is the case with virtually every publication which involves multiple contributors, the various chapters were completed at rather different times, resulting in some being more current than others. For this reason dates of receipt are included in the following brief description of the contents. In Volume I the chapter by A. F. Clark (July 1978) deals with the reductase enzymes acting at carbon-5 of the steroid molecule, with particular emphasis upon the potential hormonal activities of the products. An in-depth view of the chemistry and biochem- istry of steroid carboxylic acids is provided by H. L. Bradlow and C. Monder (Novem- ber 1977). It should be noted that the original work of these authors provided most of our current knowledge on this topic. D. G. Williamson's review (June 1977) of the biochemistry of 17 -hydroxysteroid dehydrogenases focuses upon the role of these en- zymes in the biological activation and inactivation of steroids. A. H. Payne and S. S. Singer (July 1977) discuss the role of steroid sulfotransferase and sulfatase systems from a biochemical viewpoint. In addition, they draw attention to the possible biolog- ical role of glucocorticoid sulfates. Volume II of the publication contains a chapter by B. R. Bhavnani and C. A. Woolever (August 1977) on biosynthetic pathways and some aspects of metabolism and biological activity of ring B unsaturated estrogens. This is a topic which has been primarily elucidated by the experimental work of Bhavnani. J- G. Lehoux (July 1977) reviews the complex area of the control of mineralocorticoid biosynthesis and the involvement of peptide hormones, electrolytes, prostaglandins, serotonin, etc. P. I. Musey, K. Wright, J. R. K. Preedy and D. C. Collins (July 1978) deal with steroid conjugate formation in relation to steroid distribution in body tissues and fluids. Factors related to the biological hydroxylation of 18- and 19-carbon ste- roids are discussed in a chapter by R. Hobkirk (May 1977). It is my distinct pleasure to thank each contributor for the effort put into this pub- lication. I should also like to acknowledge the help accorded me by CRC Press, partic- ularly by Coordinating Editor Benita Segraves. R. Hobkirk London, Canada THE EDITOR Dr. R. Hobkirk was born in the town of Peebles in Scotland and attended the local High School. After graduating B.Sc. with Honors in Biochemistry from the University of Edinburgh in 1952 he completed a Ph.D. degree at the same institution in 1955. This latter involved studies on the biochemistry of plant cell wall polysaccharides. The following two years were spent as a research fellow (British Empire Cancer Campaign) in the Departments of Biochemistry and Surgery, University of Glasgow. During that period studies were performed on the relationship of steroid hormones to human breast cancer. Part of the 1957-'58 year was spent as a research fellow in the Department of Biochemistry, McGill University, Montreal and then, until 1960, in the Department of Metabolism, The Montreal General Hospital, Montreal. In 1960 Dr. Hobkirk was appointed Assistant Professor in Experimental Medicine, McGill University, followed in 1962 by promotion to Associate Professor and in 1967 to Professor (Biochemistry) in the Department of Medicine. In 1966 he was appointed a Research Associate of the Medical Research Council of Canada (i.e., a full time investigatorship), an award which he continues to hold. In 1971 he moved to the University of Western Ontario, London, Canada, and is currently Professor in the Department of Biochemistry. He is occupied with research and teaching in hormone biochemistry. In 1973 he received the degree of D.Sc. from the University of Edinburgh for a thesis entitled, "Metabo- lism of the Estrogens and their Conjugates". CONTRIBUTORS Bhagu R. Bhavnani, Ph.D. Paul I. Musey, Ph.D. Associate Professor Assistant Professor of Medicine Department of Obstetrics and Emory University School of Medicine Gynecology Atlanta, Georgia McMaster University Hamilton, Ontario, Canada Anita H. Payne, Ph.D. Associate Professor of Biological H. Leon Bradlow, Ph.D. Chemistry The Rockefeller University Department of Obstetrics and Gynecol· New York City, New York ogy University of Michigan Albert F. Clark, Ph.D. Ann Arbor, Michigan Professor of Biochemistry and Associate Professor of Pathology John R. K. Preedy, M.D. Queen's University Professor of Medicine, Kingston, Ontario, Canada Associate Professor of Biochemistry Emory University School of Medicine Delwood C. Collins, Ph.D. Atlanta, Georgia Professor of Medicine Associate Professor of Biochemistry Sanford S. Singer, Ph.D. Emory University School of Medicine Associate Professor of Chemistry Atlanta, Georgia University of Dayton Dayton, Ohio Ronald Hobkirk, Ph.D., D. Sc. Professor of Biochemistry Denis G. Williamson, Ph.D. University of Western Ontario Associate Professor London, Ontario, Canada Department of Biochemistry University of Ottawa Jean-Guy Lehoux, Ph.D. Ottawa, Ontario, Canada Associate Professor, Faculty of Medicine Charles A. Woolever, M.D. Sherbrooke University Professor of Obstetrics and Sherbrooke, Quebec, Canada Gynecology McMaster University Carl Monder, Ph.D. Hamilton, Ontario, Canada Professor of Biochemistry Mt. Sinai School of Medicine Kristina Wright, Ph.D. Director, Section on Steroid Studies Instructor of Medicine Hospital for Joint Diseases Emory University School of Medicine New York, New York Atlanta, Georgia TABLE OF CONTENTS Volume I Chapter 1 Steroid A4 Reductases: Their Physiological Role and Significance ................. 1 Albert F. Clark Chapter 2 Steroid Carboxylic Acids .................................................. 29 H. L. Bradlow and C. Monder Chapter 3 Biochemistry of Steroid 17-Hydroxysteroid Dehydrogenases .................... 83 D. G. Williamson Chapter4 The Role of Steroid Sulfatase and Sulfotransferase Enzymes in the Metabolism of C21 c., and Steroids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 A. H. Payne and S. S. Singer Index ................................................................. 147 Volume II Chapter 1 Alternative Pathways of Steroid Biosynthesis and the Origin, Metabolism, and Biological Effects of Ring B Unsaturated Estrogens ............................ 1 B. R. Bhavnani and C. A. Woolever Chapter2 Factors Controlling the Biosynthesis of Aldosterone . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 J.-0. Lehoux Chapter 3 Influence of Steroid Conjugation on Excretion and Tissue Distribution ............ 81 P. I. Musey, K. Wright, J. R. K. Preedy, and D. C. Collins Chapter4 c., Hydroxylated C18 and Steroids: Their Significance and Factors Related to Their Biosynthesis ............................................................ 133 R. Hobkirk Index .................................................................. 181 Chapter 1 ALTERNATE PATHWAYS OF STEROID BIOSYNTHESIS AND THE ORIGIN, METABOLISM, AND BIOLOGICAL EFFECTS OF RING B UNSATURATED ESTROGENS B. R. Bhavnani and C. A. Woolever TABLE OF CONTENTS I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 II. Classical Pathway of Steroidogenesis ................................... 2 A. Source of Carbon Atoms of Cholesterol . . . . . . . . . . . . . . . . . . . . . . . . . . 2 B. Biosynthesis of Mevalonic Acid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 C. Formation of Isopentenyl Pyrophosphate from Mevalonic Acid . . . . . . 3 D. Formation of Squalene from lsopentenyl Pyrophosphate ............ 4 E. Cyclization of Squalene to Lanosterol . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 F. Conversion of Lanosterol to Cholesterol. ......................... 7 G. Conversion of Cholesterol to Pregnenolone ....................... 7 III. Alternate Pathways of Steroidogenesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 A. Direct Conversion of Desmosterol to Steroid Hormones ............. 9 B. Sesterterpene Pathway of Steroidogenesis ......................... 10 C. Biosynthesis of Ring B Unsaturated Estrogens ..................... 11 1. Metabolism of 7-3H-Dehydroepiandrosterone and 4-14C-Andros- tenedione Injected into the Umbilical Vein .................. 15 2. Metabolism of 1-14C-Sodium Acetate and 7-3H-Cholesterol In- jected into the Fetal Circulation ........................... 17 3. Metabolism of 14C-Squalene and 14C-Mevalonic Acid Injected into the Umbilical Circulation ............................. 20 4. Metabolism of 1-14C-Isopentenyl Pyrophosphate and (4,8,12)- 14C-Farnesyl Pyrophosphate Injected into the Fetus .......... 21 5. Theoretical Discussion on Alternate Pathways of Steroido- genesis ............................................... 24 IV. Biologic Activity of Ring B Unsaturated Estrogens ....................... 25 V. Bioassays .......................................................... 26 A. General ..................................................... 26 B. Animal Bioassay Studies ....................................... 27 1. Allen-Doisy Test ........................................ 27 2. Uterotrophic Assay ..................................... 28 3. Chick Oviduct Assay .................................... 29 C. Human Studies ............................................... 30 1. Specific Responses ...................................... 30 2. Other Responses in the Human ............................ 32 a. Hypothalamus and Pituitary ........................ 32 b. Clotting Mechanism ............................... 32 c. Metabolic Changes ................................ 32 d. Osteoporosis ..................................... 33 2 Steroid Biochemistry e. Atherosclerosis ................................... 33 f. Neoplasms of the Reproductive Organs ............... 34 D. The Metabolism of Equilin in Man ............................... 35 1. Intravenous Equilin Sulfate ............................... 35 2. Intravenous 3H-Equilin .................................. 36 VI. Concluding Remarks ................................................ 42 Acknowledgments ........................................................ 43 References ............................................................... 43 I. INTRODUCTION For the past 25 years, it has been generally accepted that cholesterol is the obligatory precursor in the biosynthesis of all steroid hormones. Details of the various steps for the synthesis of cholesterol from acetate and for its conversion to steroids were estab- lished mainly by in vitro incubation procedures using tissues such as the ovary, testis, and adrenal cortex. Although it became firmly established that acetate was the initial two carbon source of cholesterol, some experimentation suggested that cholesterol may not be the only precursor from which all steroid hormones are formed. This chapter will discuss the evidence for the steroidogenic pathway which bypasses cholesterol. It will be referred to as the alternate pathway of steroidogenesis, while that which utilizes cholesterol as an obligatory intermediate will be termed the classical pathway of steroidogenesis. Although it is not the purpose of this chapter to discuss the classical pathway of biosynthesis and metabolism of steroid hormones, ·its salient features will be reviewed briefly to facilitate comparison with the alternate pathway, which will be discussed in detail. The metabolism and biological action of the ring B unsaturated estrogens will also be presented. II. CLASSICAL PATHWAY OF STEROIDOGENESIS The various steps in the classical pathway of steroidogenesis from acetate are acetate -+ mevalonic acid -+ isopentenyl pyrophosphate -+ 3,3-dimethyl allyl pyrophosphate -+ geranyl pyrophosphate -+ farnesyl pyrophosphate -+ squalene -+ lanosterol __.. cho- lesterol-+ pregnenolone -+ steroid hormones. The details are discussed below. A. Source of Carbon Atoms of Cholesterol Studies by Bloch, Lynen, Cornforth, Popjak, and their colleagues on cholesterol biosynthesis from either methyl or carboxyl 14C-labeled acetate established that all 27 carbon atoms of cholesterol are derived from acetate. These investigations have been reviewed by Bloch. 1 The distribution of the 15 methyl and 12 carboxyl carbons in cholesterol is shown in Figure 1. This arrangement of the carbon atoms of acetate in cholesterol follows the "isoprene rule," which was defined by Ruzicka as a working hypothesis as early as 1921.2 B. Biosynthesis of Mevalonic Acid Three molecules of acetic acid in the form of acetyl-CoA (coenzyme A) thioester 3 FIGURE I. Distribution of carboxyl(C) and methyl(M) carbons of acetic acid in cholesterol. 0 0 0 11 fi-KETOTHIOLASE II II 2CH 3 -C-5-CoA CH rC-CH2-C-S-CoA Co-ASH ACETYl-GoA ACETOACETYl-GoA COENZYME A + Co-ASH 3-HYDROXY-3-METHYL GLUTARYL-CoA MEVALONATE-NADP OXIDO ~ 2 NADPH + 2H+ REDUCTASE EC 111 34 ~ 2 NADP+ H3C /OH OJ=C' c"{'-< ;-"' -cH( C'H-'2o " 3R'-MEVALONIC ACID FIGURE 2. Biosynthesis of mevalonic acid from acetyl coenzyme A. condense to form mevalonic acid (Figure 2). All of the intermediates involved are bound to coenzyme A, and the required enzymes are present in both the cytoplasmic particles and the soluble fraction of mammalian and avian liver3 6 and in yeast. 78 The - ' first step, catalyzed by a soluble enzyme (3-keto-thiolase, results in the formation of acetoacetyl-CoA. In the presence of 3-hydroxy-3-methyl-glutaryl-CoA synthase (which is located in the mitochondria and the soluble fraction of liveruo but not in the micro- somal fraction as had been reported previously'u2 the acetoacetyl-CoA condenses ), with a third molecule of acetyl-CoA to give 3-hydroxy-3-methyl-glutaryl-CoA (HMG- CoA), the immediate precursor of mevalonic acid. The reduction of this precursor to mevalonic acid is catalyzed by mevalonate: NADP• oxidoreductase (EC 1.1.1.34), which is present in both yeast mitochondria 13 and in the mammalian liver micro- somes. 'us This microsomal system is thought to be the rate-limiting step in the biosyn- thesis of cholesterol in mammalian liver.1u 6 17 Although this scheme is generally be- , lieved to be the major pathway of mevalonate biosynthesis, an alternate minor pathway involving malonyl-CoA has been described by Brodie et al. '8 9 The mecha- ·' nisms involved in these transformations have been recently reviewed by Beytia and Porter.20 C. Formation of lsopentenyl Pyrophosphate From Mevalonic Acid The biosynthesis of isopentenyl pyrophosphate (IPP) from 3R-mevalonic acid is cat- alyzed by soluble enzymes and involves phosphorylated intermediates. Mevalonic acid is sequentially phosphorylated first (Figure 3) with ATP in the presence of mevalonic