Monographs on Endocrinology – serie

We live in an era of "explosions". Not the least threatening of these inflationary events is the information explosion. In spite of data banks, automated indexes, and computerized retrieval systems, science is being overflooded by its products. Much of the responsibility for this state of affairs must rest with a system that tends to reward quantity rather than quality of publications, and on the resulting misap­ prehension that the aim of scientific research is the gathering of data rather than the advancement of knowledge. The sponsors of congresses and symposia who insist on a lasting record of their proceedings, the authors and editors who have no compunc­ tion about printing trivial or redundant information, and the publishing houses them­ selves, which can hardly be expected to favor restraint, also bear part of the respon­ sibility. One of the consequences of the information explosion is a change in our attitude towards new books. Whereas we used to welcome their appearance and to take them as useful and good until proven otherwise, we now greet them with suspicion and wonder even before opening them whether they were really necessary. Fortunately, some of them still are and perform a real service by taking an unwieldy mass of data dispersed in a variety of journals, and organizing it into a coherent synthesis of the state of knowledge in a given field. Such books actually serve to advance knowledge and become landmarks.

The contents of this monograph "Hypothalamic Control of Lacta­ tion" are the result of studies by a nine-man team which has worked together for nine years. The topic is so fascinating that new research students are attracted to it every year, and the circle is growing steadily. This is, in fact, part of a much more extensive research field to which our Department is applying itself at present, viz. "Hypo­ thalamic Pharmacology". Our work in this sphere was made possible by a generous grant from the United States Department of Agriculture, which helped us during the first 5 years of research with Grant No. FG-IS-147, Project No. A10-AH-3, and recently with another grant for a further 5-year period, No. FG-IS-259, Project No. A10-AH-33. Our thanks are due to Dr. JOEL BITMAN, Hormone Physiology Leader of the USDA Agri­ cultural Research Service at Beltsville, Md., the sponsor of this research. As this monograph contains mainly references connected with our own work, the reader who wishes to make a survey of lactation should study the references cited in the bibliography, such as COWIE (1961, 1966), COWIE and FOLLEY (1957, 1961), FOLLEY (1952, 1956), JACOB­ SOHN (1961), LYONS and DIXON (1966), MEITES (1959a, 1961, 1966), MEITES and NICOLL (1966).

This is the story of steroid-protein interactions as one investigator sees it. Following the general concept of this monograph series, it emphasizes the results and interpretations obtained in the author's laboratory, and is therefore a subjective account. Recognizing, how­ ever, that the discussion of the subject would be incomplete if the material were limited to one scientist's work, the essential achieve­ ments of other investigators have been incorporated. An effort has thus been made to give a balanced presentation and to enable the reader to see in perspective the varied facets of the interactions between steroids and proteins. Since this is the first comprehensive treatment of the topic, it seems appropriate to go to the roots, and try to find out how it all started. The first chapters, therefore, take the reader to the laboratories of those who very early conceived the significance of the attachment of dyes, drugs, and other conspicuous molecules to those colloids called proteins. The discovery of the steroid hormones set the stage for meaningful investigation of their interaction with proteins of various origins and functions - a process which is continuing today with increasing vigor.

Soon after the discovery of insulin in 1922, it became clear that the use of this hormone in the treatment of diabetics is often accom­ panied by allergy. In 1956 it became possible to determine quantita­ tively the insulin-binding antibodies which are responsible for the resistance to insulin. The methods developed since then make it possible to measure minute amounts of the pancreatic hormone in blood and extracellular fluids. There have been many attempts to relate insulin allergy and in­ sulin resistance to the primary, secondary or tertiary structure of the or B chains, or both, and more recently, to the proinsulin which is A present in all commercial preparations of insulin, i. e. to the species­ specific structure of the C peptide. In the great majority of papers dealing either with the immunogenic and antigenic properties of in­ sulin or with the relevant antibodies, the discussion has been restricted to the humoral antibodies. The existence of a brief period of delayed local allergy resulting from the cellular immune response has more or less escaped attention. It is specifically this period of delayed allergy that attracted the interest of Dr. FEDERLIN and his colleagues. Making use of immuno­ histological and other techniques which are rarely employed in clinical observation, and with the help of experiments on animals, Dr. FEDERLIN traces the course of insulin allergy from cellular immunity, through the production of humoral antibodies by the insulin-binding cells of the circulation, to the sessile immunological apparatus.

This book was written at the invitation of Dr. H. GOTZE of Springer-Verlag for the series "Monographs in Endocrinology". It is not a comprehensive account of the prostaglandins but has been writ­ ten with a deliberate emphasis upon those aspects of the field in which I am particularly interested and to which, in some cases, I have made a contribution. I am grateful to Miss E. PFISTERER and her colleagues of Springer­ Verlag for their excellent work. I should also like to thank my wife without whose patience, encouragement and help this book would never have been completed. Finally this is an appropriate time to express my sincere gratitude to those scientists who over the years have given me samples of prostaglandins-namely Professors S.BERGSTROM and B.SAMUELSSON of the Karolinska Institute, Stockholm, Professor D. A. VAN DORP of the Unilever Research Laboratories, Vlaardingen and Dr. J. E. PIlm of the Upjohn Company, Kalamazoo. Without their help work in this field would have been extremely difficult.

The purpose of this monograph is to describe theoretical aspects of the interpretation of data obtained from experiments performed with labeled hormones. Quantitative endocrinologic studies involving the use of tracers include the determination of rates at which hormones are secreted by endocrine glands and are produced outside these glands by conversion of other secreted hor­ mones. Tracer experiments are also performed with the purpose of measuring rates of metabolic reactions. These measurements reveal the contribution of secreted hormones to the formation of circulating compounds and urinary metabolites. The estimation of rates of fetal and placental production and exchange of hormones characterizes a class of in vivo quantitative studies performed with isotopically labeled hormones (radioactive or not). In addi­ tion, tracers are used to measure permeability and rates of reaction in in vitro systems, and to study the uptake of hormones by tissues, both in vivo and in vitro. The stability of the steroid nucleus carrying the isotopic label and the large number of reversible metabolic reactions in which steroids are involved, both facilitated and motivated the development of a sophisticated theoretical treat­ ment of tracer experiments in the field of endocrinology. Although the prac­ tical examples used to illustrate the concepts and calculations presented in this monograph involve labeled hormones, the theory is presented in a general symbolic manner and is applicable to other fields of investigation.

It has become increasingly evident within the last few decades that immunologic factors are involved in some aspects of the reproductive process and hence in the physiology and pathology of the genital tract. The concept that immune phenomena participate in human reproduction is not new. There are examples throughout the history of man that immune phenomena may have influenced the reproductive process. For example, the Bible states that Sarah was sterile for a long time but conceived in the later years of her marriage. This could be interpreted to mean that continued exposure to her husband's ejaculated antigens re­ sulted in antibody response, sufficient to induce sterility. However, after continence of long duration, the antibody level declined and conception became possible. Another of speculation is Darwin's Descent of Man, which contains a number of state­ source ments to the effect that profligacy of women may account for their "small fertility". The inference is that repeated exposure to antigenic material in the ejaculate causes antibody responses that lead to infertility (KATSH and KATSH, 1965). This is directly related to the modern postulate that prostitutes do not conceive because of antisperm antibodies acquired by frequent contact with semen.

Upon wresting the control of the earth from the Titans, Zeus assigned the task of creating living creatures to two Titan brothers who had sided with him in the epic battle just concluded. Because Epimetheus, who had been endowed only with hindsight, had the first hand in this creation, all the good attributes were exhaus­ ted by the time the lion, the elephant and other animals were created. When the time came for the creation of man, there were precious few materials left to work with. Not surprisingly, man was made weak and naked. Prometheus took pity on this miscreation and gave man the use of fire. For this foresight, Zeus meted out horrible punishment, binding Prometheus to a rocky pillar in the Caucasas Moun­ tains and letting a vulture consume his liver daily. It seems to me that the ancient Greeks in their unfathomable wisdom under­ stood the essence of the evolutionary process very well. Had Escherichia coli of 200 million years or so ago been endowed with the foresight to anticipate the eventual emergence of and subsequent dominance by mammals of this Earth, they would no doubt have equipped themselves, in anticipation of the coming cer­ tainty, with the lac operon to deal with lactose in the suckling mammalian infant's gut. Had they been able to do so, the actual emergance of mammals would have exerted no selective pressure upon existing E. COLI.

Because diseases of the bone are often less acute and less lifethreatening than dis­ eases of the circulatory system, gastrointestinal tract, kidney, liver, and the nervous system, they have received a disproportionately smaller amount of attention in the medical world. With the average increasing life span of man as a result of improve­ ments in modern medicine, espe~ially in the pediatric field, the seriousness of many metabolic bone diseases has indeed become more obvious. In addition, other improvements in medicine, such as hemodialysis for the preservation of renal failure patients, have permitted the development of other consequences of diseased kidneys, one of which is the appearance of renal osteodystrophy. Finally, the appearance of several genetic disorders in the area of metabolic bone disease has been underscored by the solution of other pediatric diseas~s of much more serious consequences. These emerging problems all suggest that much remains to be learned concerning the sys­ temic control of bone, both as a structural organ and as a reservoir for the important elements of calcium and phosphorus so essential for the support of life in complex multicellular organisms of which man is the most important. As will be demonstrated in the historical portion of this manuscript, the existence of the three most important humoral factors regulating bone metabolism and func­ tion are now known.

It is the object of this series of monographs to present the experiments and interpre- tations of a given laboratory. We have attempted in this volume to present our view of receptor-steroid interactions and their relation to steroid-induced responses. This view is necessarily biased by our own experimental results. While we have tried to in- clude the views and results of others, this volume is not meant to be comprehensive. Rather it is selective and examines those topics within the general field of steroid hor- mone action which we have addressed at the laboratory bench. The work reviewed in this volume would not exist without the help and support of many associates. Our mentors included Jorge Awapara, Jack Gorski, Henry Komer, Bill Ray, and Mike Zarrow. Associates instrumental in this work include George Barr, John Burgner, Sam Campbell, Constance Cardasis, Hitkan Eriksson, Stan Glasser, Jim Hardin, Mohammed Kalimi, Bruce Lester, Barry Markavarich, Shirley McCormick, Tony Means, Dan Medina, Ann Miller, Bert O'Malley, Helen Padyku- la, Zigmund Paszko, Dale Snow, Susan Upchurch and Marian Walters.Students who have contributed to this effort include John Anderson, Joe DeLibero, Aaron Hsueh, Katrina Kelner, Debbie Metzger, Randy Richards, Jim Schaeffer, Mike Tytell, Lane von Brunt, and Cheryl Watson. Technicians without whose assistance this work could not exist include Toni Cetti, Wendy D'Attilio, Jeanie Haselby, Lily Hsueh, Helen Hyland, Jim Kovar, Kathy O'Connor, and Peggy Sansone.

Research on the hormonal control oflactation - the subject of this monograph - has long been the major interest of this laboratory. Studies were initiated in the mid 1930s by the late Professor S. 1. Folley, FRS, who directed the work with immense enthusiasm and devotion until his untimely death in 1970. This fruitful area of basic and applied research has, in recent years, attracted widespread attention; there have been many exciting events and developments with a dramatic increase in the number of publications. These events are diverse and include the identification, isolation and sequencing of human prolactin; the identification and isolation of placentallactogens in several ruminant species with recognition of their importance in mammary growth and differentiation; the introduction of highly sensitive bioassay, radioimmuno- and radioreceptor-assay techniques for mammotrophic hormones; the growing clinical appreciation of the immunological and nutritional importance of colostrum and milk to the newborn; the intensification of studies on normal mammogenesis to establish a sound basis for studies on mammary cancer; and the exploitation of the mammary gland, with its characteristic differentiation patterns and multiple synthetic abilities, as a valuable tissue for the investigation of basic mechanisms involved in the synthesis under hormonal control of enzymes and secretory proteins; and for the study of hormone - receptor interactions.

The building of conceptual models is an inherent part of our interaction with the world, and the foundation of scientific investigation. Scientists often perform the processes of modelling subconsciously, unaware of the scope and significance of this activity, and the techniques available to assist in the description and testing of their ideas. Mathematics has three important contributions to make in biological modelling: (1) it provides unambiguous languages for expressing relationships at both qualitative and quantitative levels of observation; (2) it allows effective analysis and prediction of model behaviour, and can thereby organize experimental effort productively; (3) it offers rigorous methods of testing hypotheses by comparing models with experimental data; by providing a means of objectively excluding unsuitable concepts, the development of ideas is given a sound experimental basis. Many modern mathematical techniques can be exploited only with the aid of computers. These machines not only provide increased speed and accuracy in determining the consequences of model assumptions, but also greatly extend the range of problems which can be explored. The impact of computers in the biological sciences has been widespread and revolutionary, and will continue to be so.

The cytochemical bioassay system was described in a short abstract in 1971, and more fully, in the cytochemical bioassay of corticotrophin, in 1972. Since then, cytochemical bioassays have been described for several polypeptide hormones, and these assays are already widely used. It is expedient that the subject should be reviewed, as it is in this monograph, by one writer who has had the good fortune to have taken part in the growth of cytochemistry from its early origins to its present position as the basis of possibly the most sensitive bioassay system currently available. However, it should be noted that major contributions have been made by many, both to the development of the subject and to the establishment of the bioassays. The object of this preface is to try to give some perspective to the growth of this subject and to record that the cytochemical bioassay system has been fostered by many outstanding scientists in an atmosphere of remarkable goodwill. To begin with, there could have been no cytochemical bioassays until cytochem­ istry had been converted from its rather unsure origins into a precise and quantitative form of cellular biochemistry. This was done with skill and enthusiastic dedication by my colleagues, Dr. Lucille Bitensky, Dr. F. P. Altman, Dr. R. G. L. W. Poulter and Mr. A. A. Silcox, first at the Royal College of Butcher, Dr.

The physiology and metabolism of thyroid hormones were areas of intense research investigation during the 1970s. Radioimmunoassays were applied to study the concentration of iodothyronines in biologic fluids. These techniques proved to be highly sensitive, specific, and reproducible as well as rapid. The availability of specific radioimmunoassays led to the detection of several iodothyronines in human biologic fluids, e. g., reverse triiodothyronine (rT 3), diiodothyronines, monoiodothyronines, and acetic acid derivatives of thyroxine (T 4) and T 3, which were previously either unknown or briefly considered but forgotten in the 1950s. This monograph is intended for readers who desire an overview of thyroid hormone physiology as it was understood in 1979. It should be especially useful to trainees in endocrinology and individuals interested in potential research projects. The main focus has been on the studies conducted between 1969 and 1978, alt~lOugh other information has been reviewed to provide an overall working knowledge of the field. A list of over 500 references, although probably still incomplete, should lead a reader to at least a few important articles in each area relevant to thyroid hormone physiology.

In the past 10 years hirsutism has been the object of a considerable number of fundamental studies. It provides endocrinologists with an experimental model for the investigation of androgen secretion, metabolism and mechanism of action. Plasma androgen assay, free testosterone measurement, hepatic and extrahepatic androgen metabolic clearance and androgen metabolism in the skin are the different steps which were studied by many groups and represent valuable parameters of the mechanisms of hirsutism. Determination of the origin of androgen oversecretion has become easier by technical progress in differential effiuent venous catheterism, which makes it possible to compare androgens in adrenal or ovarian effiuent veins to their peripheral levels, and to determine the ovarian or adrenal source of the androgen oversecretion as well as the side responsible, essential in the case of tumors. The study of androgen metabolism and the discovery of androgen receptors in the skin confIrm the latter as an actual target cell for androgens. This target cell uses the circulating active androgen, i. e. , testosterone and can also metabolize local inactive androgens into active ones. This is the case of androstenedione and dehy­ droepiandrosterone which are the two main androgens secreted in women, since women secrete very little testosterone. The capacity of the skin to transform inactive androgens into active ones varies from one individual to another. That would support the concept of variable skin receptivity from one woman to another and from one ethnic group to another.

The present monograph will concern itself with those disorders of the endocrine system, either associated with destruction, interference with function or hyper- function, which are considered to be due to auto-immune processes. Endocrinopathies Non-endocrine auto-immune disorders associated with the endocrinopathies Graves' (Basedow's, Parry's) disease Pernicious anaemia Hashimoto's thyroiditis Vitiligo Idiopathic Addison's disease Myaesthenia gravis Insulinopenic diabetes mellitus Sjogren's syndrome Auto-immune oophoritis and orchitis Rheumatoid arthritis Auto-immune hypoparathyroidism Idiopathic thrombocytopenic purpura Auto-immune hypophysitis Chronic active hepatitis Possibly some cases of infertility Primary biliary cirrhosis due to anti-sperm antibodies Reproduced with permission from Volpe (1977) The above table indicates those organ-specific endocrinopathies considered to be due to auto-immune factors, as well as those non-endocrine, organ-specific auto-immune disorders which may be associated with them (Volpe 1977).It is evident that such disorders, occurring without any obvious external cause, raise the very elementary question of how immune processes directed against self- constituents could be initiated. Generally, of course, the immune system acts as a regulatory and defence mechanism, and disorders of auto-immunity represent breakdowns in this regulatory system. The following chapters will be concerned with the individual components ofthe endocrine system so affected by auto-immune processes; it will first be necessary to provide an initial chapter for the purpose of summarizing some general principles of immunology, in order to place the immune disorders of the endocrine system in context.

This monograph represents the first comprehensive review of hormones in human amniotic fluid and includes data published up to and including 1980. Recently, more extensive use of amniocentesis for prenatal diagnosis and evaluation of fetal lung maturation has shown that amniotic fluid hormone measurements can aid in the diagnosis of fetal and placental abnormalities. The material is presented in two main sections dealing with steroid and protein hormones. The methods of identification and quantitation are delineated, and the findings are discussed in relation to the clinical conditions. In addition, particular attention has been directed towards up-to-date review of the sources, metabolism and transfer of human amniotic fluid hormones. The review is intended to serve the needs of clinicians, basic scientists and students, providing detailed information on human amniotic fluid hormones in order to improve patient care and indicate possibilities for further investigations. Ttibingen, January 1982 A.E. Schindler Contents Introduction A. 1 Origin of Human Amniotic Fluid . 2 B. C. Origin and Regulation of Steroids in Human Amniotic Fluid . 5 D. Methods of Isolation and Identification of Steroids in Human Amniotic Fluid 6 I. C , C , and C Steroids . 6 30 29 28 II. C Steroids 6 27 1. Cholesterol 6 2. Cholestanol . 6 3. ,::l7 -Cholestenol and ,::l8 -Cholestenol. 6 4. 7-Dehydrocholesterol and Desmosterol . 6 ,::l5_C Steroids. III. 7 21 1. Pregnenolone 7 2. 16cx-H ydroxypregnenolone. 7 3. 17cx-Hydroxypregnenolone.

The unraveling of our knowledge of the functions of the adrenal gland constitutes one exciting development of modern medicine and biochemistry. We owe these advances to the felicitous cooperative efforts of the clinical investigator and the biochemist. Three centuries elapsed between the first recorded anatomical descrip­ tion of the adrenals and the demonstration by Dr. Addison in the mid-nineteenth century of the fatal results of the destruction of these glands by disease. It became evident from this observation that the adrenals secreted a "factor" or "factors" essential to life. It took approximately 90 years to isolate this elusive vital factor - cortisone - from beef adrenal cortices, independently by both Reichstein and his co-workers in Basle and Kendall and his group in the United States and another 10-15 years before it became more generally available for experimental and clinical use. It is perhaps difficult to believe that as recently as 35-40 years ago, before cortisone and cortisol were clinically available, the surgical removal of a benign adrenal cortical tumor in patients with Cushing's syndrome was associated with a prohibitive postoperative mortality rate. Within 12-36 h after operation, most of such patients developed an intractable state of shock, which was not manifested by significant electrolyte abnormalities or hypoglycemia and was unresponsive to the usual treatment for shock plus the generous use of salt-retaining hormone.

Lactogenic hormone activity was first observed in bovine pituitary extracts by Stricker and Griiter in 1928, working in Bouin's laboratory in Strasbourg. Since that time prolactin has been shown to exist in anterior pituitary extracts of almost all vertebrate species investigated. Although its biology was extensively studied in many mammalian species, the existence of prolactin in the human was generally doubted, despite the positive evidence produced by such researchers as Pasteels. This can partly be explained by the fact that human growth hormone isolated in 1961, is itself a potent lactogen, in contrast to nonprimate growth hormones, and is present in the normal human pituitary in much greater amounts than prolactin. As a result there was a lag of nearly 10 years until prolactin was unanimously accepted as a hormone of the human pituitary, separate from human growth hormone. In 1970 new bioassay techniques permitted the demonstration of prolactin bioactivity in the serum of postpartum women and galactorrhea patients, and chromatographic methods led to the isolation and purification of human prolactin allowing the establishment of a specific radioimmunoassay for this hormone. This opened the road to the understanding of prolactin physiology and pathophysiology in the human, which has revolutionized clinical neuroendocrinology and reproductive endocrinology. Particularly hyperprolactinemia has turned out to be one of the most common endocrine syndromes.

Dr. Raymond Pederson, Dr. Jill Dryburgh and I commenced work on GIP in 1968, when, with the generous help of Professor Viktor Mutt and Professor Erik Jorpes of the Karolinska Inst,itute, Stockholm, we were able to establish that there existed an inhibitory material for acid secretion in cholecystokinin-pancreozymin prepara­ tions. Once the physiological evidence for the inhibitor was established it seemed appropriate to seek help in its isolation. Dr. J. Dryburgh and Dr. R. Pederson were left to bioassay fractions in Vancouver whilst I enjoyed the company of Professor Mutt at the Karolinska for one year, as a Medical Research Council of Canada Visiting Scientist. Purification of the inhibitory factor proceeded rapidly due, in no small measure, to Professor Mutt's untirmg efforts on my behalf. Later that year, Dr. Dryburgh joined us in Stockholm to begin the sequence work on GIP. This was completed late in 1970 in Vancouver. In Stockholm in June 1970, I met a fellow Canadian Dr. John Dupre (McGill University) at a cocktail party who kept commenting about the possibility of GIP being an insulinotropic hormone, the "incretin" of earlier days. At that time, gastrointestinal physiologist as I was, I did not recognize the importance of his comment. This became apparent two or three years later when Dr. Dupre demonstrated that GIP was insulinotropic in man. In 1972, Maryanne Kuzio and Dr.

This monograph brings together our work concerning the relationships be­ tween the hypothalamus, pituitary and testis. The studies span approximate­ ly a decade of collaborative work. Over this period our contributions and those of many others have advanced greatly our understanding of many aspects of male reproductive biology. This monograph attempts to survey these developments and to highlight many unresolved issues. It also provides an opportunity to demonstrate the value of investigations which relate bio­ chemical to structural parameters and to illustrate the importance of animal studies in elucidating biological principles with clinical applications. The reverse is also important since the pathophysiology of human disorders of­ ten provides insight into hitherto unsuspected basic mechanisms. In any rapidly expanding field it is difficult to stop revising and extending a manuscript. It is equally difficult to quote every reference in the field but we trust that those of significance have not been omitted. Some of our former students have collaborated with us as co-authors in producing this monograph. It is equally important to recognise the contributions of our other former students and colleagues who have physically participated in the studies and without whose intellectual contributions a number of concepts would not have been elucidated. Their work is acknowledged in the text of the monograph and the extensive list of references.

Congenital adrenal hyperplasia (CAH) consists of a group of disorders of adrenal steroidogenesis. Each disorder results from an inherited deficiency of one of the several enzymes necessary for normal steroid synthesis. The different enzyme deficiencies produce characteristic patterns of hormonal abnormalities; the clinical symptoms of the different forms of CAH depend on the particular hormones that are deficient or that are produced in excess. The earliest documented description of CAH was by DeCrecchio in 1865 (DeCrecchio 1865). This Neapolitan anatomist described a cadaver having a penis with first degree hypospadias but no externally palpable gonads. Dis- section revealed a vagina, uterus, fallopian tubes, ovaries, and markedly enlarged adrenals. It is interesting that the subject suffered a confusion of sex assignment, being declared a female at birth and a male 4 years later. He conducted himself as a male sexually and socially. Since the original descrip- tion of this case, investigators have unravelled the pathophysiology of the inborn errors of steroidogenesis. 1 Steroidogenesis and Enzymatic Conversions of Adrenal Steroid Hormones A.Steroidogenesis The adrenal synthesizes three main classes of hormones: mineralocorticoids (17-deoxy pathway), glucocorticoids (17-hydroxy pathway), and sex steroids.

As I reflect on the evolution of this book, I am struck by the differences be­ tween my early conceptions and the final product. When I was first ap­ proached by Springer-Verlag regarding a monograph on my interests in the area of fetal lung development, I imagined that it would be relatively easy to summarize my contributions, plus the work of other investigators as needed for proper perspective. This rather naive idea was abandoned as I prepared my initial outlines for the monograph. I quickly realized that con­ tributions from my laboratory are not sufficient for telling the story of "hormones and lung maturation". The result of this decision is a longer and more heavily-referenced book than I originally envisioned. Although I have attempted to discuss in considerable detail most aspects of hormones and the fetal lung, I know with certainty that I have not in­ cluded all relevant references in each area. In most of these instances this reflects my impatience or lack of diligence, and I offer my apologies to those investigators whose work has been so omitted. In some situations published work has not been cited in a deliberate decision to limit the breadth of discussion or, rarely, due to my judgment of major shortcom­ ings in experimental design or execution.

Sixteen years is a long time, not only in human life but also in the rapid history of contemporary endocrinology. Since the publication of the first edition of this monograph, numerous new lines of research and discoveries have greatly contrib- uted to our knowledge of the physiological and pathological regulation of aldos- terone biosynthesis in man and animals. The first reports about a sensitive ra- dioimmunoassay for plasma aldosterone and about a preparation of dispersed zona glomerulosa cells were published in 1970 (Mayes et al. 1970; Haning et al. 1970). These two developments alone turned out to have a tremendous impact on research in aldosterone physiology (for reviews see Coghlan et al. 1979b; J. F. Tait et al. 1980b). In 1971, atrial natriuretic peptides, somatostatin, and the precursor molecule of ACTH had not yet been discovered. Angiotensin antagonists and con- verting-enzyme inhibitors were not yet available. The clinical syndrome of hypo- reninemic hypo aldosteronism was unknown. The possible roles of prostaglandins and dopamine in the control of aldosterone pwduction had not been considered.Cyclic AMP was then the only substance with a clearly established second-mes- senger function.

This book originates from a symposium held at the London Hospital Medical College under the auspices of Applied Chromatography Systems Ltd. to discuss the place of HPLC in the endocrinology field. Many of the authors of the present book were speakers at this symposium. It seemed to us that many endocrinolo­ gists did not at that time fully appreciate the value of HPLC, and this book was designed to publicise the potential value of this technique. A survey of methods used in the steroid field Cp 185) confirmed the view that HPLC is not being used as widely, particularly in research described in clinical journals, as might be expected. We hope that this book will illustrate, albeit in a few selected areas of endocrinology, just how versatile and powerful a technique HPLC is, and en­ courage those who have not yet experienced it to have a go. The beginner does not need to buy expensive instrumentation - all that is required is a pump, injector, column and detector - the rest can come later! All the authors have practical experience in the use of HPLC in the particular area they discuss. All readers who discover apparent errors or who feel that the treatment of a topic of interest can be improved upon are encouraged to contact the editors. All criti­ cism, especially if constructive, is welcomed. We are still learning, and other peoples' experience is always valuable.

The account of "neonatal sterilization" is the story of the advocates of direct effect of steroids on the gonads and those who believed in the indirect influence, mediated through the hypothalamus and/or the pituitary gland. As often happens in biology, both convictions represent the same image seen from different perspectives. Prof DC Johnson (Kansas City, KS) reminisced the beginning of the story in a letter to me. I am paraphrasing parts of the letter with his permission. "As a starting point we could pick the life-long research of Emil Steinach ... " Steinach recognized the influence of testes on the develop­ ment of accessory sex organs in 1894, described virilization of females and feminization of males in 1913, and identified the controlling influence of the hypophysis on the gonads in 1928. He reviewed his work in a book Sex and Life, Forty Years of Biological and Medical Experience (E Steinach and L Loebe!; Faber and Faber, London, 1940). He got on the wrong road in later years and that is the reason everybody seems to have forgotten him. He presented his hypothesis that estrogen has a direct effect upon the testes, i. e. hormone antagonism, at the 1st International Congress on Sex Research in 1926.

It has been my privilege and pleasure during the past half century to participate in the unfolding of present-day concepts of the mammalian female reproductive cycles. When the studies recorded here began in the late 1930s it was already established that cyclic ovarian function is governed by gonadotropic secretions from the anterior pituitary gland, the "conductor of the endrocrine orchestra," and that in turn this activity is importantly dependent in some way upon secretion of estro­ gens and progesterone by the ovaries. Although a role of the nervous system was recognized for the reflex-like induction of ovulation in rabbits and cats and the in­ duction of pseudopregnancy in rats and mice, and although there was even some evidence of neural participation in ovulation in rats, a major central neural role in the female cycle of most species was not apparent. Gonadotropic fractions of pitui­ tary extracts having distinct follicle-stimulating and luteinizing activities in test ani­ mals had been obtained, and these respective effects had been fairly well charac­ terized. Prolactin was well known for its lactogenic activity, but its luteotropic role in rats and mice had yet to be revealed. The molecular structure of the several estro­ gens and progesterone was known, and they were readily available as synthetic pro­ ducts. The broad concept of ovarian-pituitary reciprocity appeared to be an accept­ able explanation of the female cycle, with the ovary in control through the rhythmic rise and fall in secretion of follicular estrogen.

Few fields have advanced faster over the past quinquennium than separation and estimation of steroids by the technique of gas phase chromatography. A detailed and complete review of this topic would therefore be beyond the scope of the authors contributing to this monograph. It was, however, felt that a discussion of some of the highlights of this rapid advance might be of help for laboratories estimating steroids in biological samples. One of the difficulties in producing a monograph of this kind is that before it can appear in print it is likely that some of the methods it discusses will have been overtaken by better methods, so swiftly is progress now made. No editorial power has been exercised in trying to make a uni­ form account of technology in this field, and the idiosyncrasies of each individual author have been left intact. Through this approach we hope that what has been lost in scholarly appearance is regained in general appeal.