Current Topics in Experimental Endocrinology, Volume 5: Fetal Endocrinology and Metabolism covers various aspects of fetal endocrinology. The book discusses studies of the hypothalamic-pituitary unit which emphasize the unique aspects of the fetal endocrine system; in vitro fertilization; and factors controlling placental endocrine function in domestic animals. The text also describes the role and kinetics of thyroid in fetal development; the placental transfer of carbohydrates; and fetal hormones and carbohydrate utilization. The regulation of partition of protein during pregnancy; the mineral needs of the fetus; and the fetal metabolism of cortisol are also considered. The book further tackles normal and abnormal sexual differentiation and the metabolic errors of adrenal steroidogenesis. Physiologists, endocrinologists, obstetricians, gynecologists, and students taking related courses will find the book invaluable.
Front Cover 1
Fetal Endocrinology and Metabolism 4
Copyright Page 5
Table of Contents 6
CONTRIBUTORS 10
PREFACE 12
CHAPTER 1. THE FETAL NEUROENDOCRINE AXIS 16
I. Introduction 16
II. The Development of the Hypothalamus and Adenohypophysis 18
III. The Secretion and Function of Fetal Adenohypophyseal Hormones (see Fig. 1) 22
IV. Autonomy of the Fetal Neuroendocrine Unit 43
Acknowledgments 45
References 46
CHAPTER 2. IN VITRO FERTILIZATION 58
I. The Natural Ovulatory Cycle and IVF 59
II. The Stimulated or Controlled Ovulatory Cycle 69
III. Maturation of the Oocyte 76
IV. The Technique of in Vitro Fertilization 78
V. The Use of IVF in Male and Idiopathic Infertility 85
References 86
CHAPTER 3. FACTORS CONTROLLING PLACENTAL ENDOCRINE FUNCTION IN DOMESTIC ANIMALS 90
I. Introduction 90
II. Control of Placental Steroid Secretion by Fetal Cortisol in Domestic Animals 92
III. Control of Secretion of Placental Lactogens 103
IV. Effects of /3-Catecholaminergic Drugs on the Placenta 105
V. Conclusions 106
References 108
CHAPTER 4. THE FETAL THYROID 112
I. Introduction 112
II. The Choice of Preparation 113
III. The Morphological and Secretory Development of the Gland 114
IV. The Placental Barrier 117
V. The Role of the Thyroid in Fetal Development 119
VI. Fetal Thyroid Hormone Kinetics 121
VII. Perinatal Thyroid Hormone Concentrations 124
VIII. Conclusion 128
Acknowledgment 129
References 129
CHAPTER 5. CARBOHYDRATE METABOLISM 132
I. Introduction 133
II. Maternal Hormonal and Metabolic Adaptations 133
III. Early Embryonic Development 139
IV. Placental Transfer of Carbohydrates 141
V. Fetal Hormones and Carbohydrate Utilization 148
VI. Fetal Metabolic Pathways 152
VII. Summary 153
References 153
CHAPTER 6. REGULATION OF PARTITION OF PROTEIN DURING PREGNANCY 160
I. Introduction 161
II. Placental Protein 161
III. Fetal Protein 166
IV. Free Amino Acid Pools 174
V. Maternal Protein 181
References 188
CHAPTER 7. MINERAL NEEDS OF THE FETUS 192
I. Introduction 193
II. Calcium, Phosphate, Magnesium 193
III. Parathyroid Hormone (PTH) 194
IV. Vitamin D 196
V. Calcitonin 202
VI. Hormone Interrelations 206
VII. Conclusion 208
References 208
CHAPTER 8. FETAL METABOLISM OF CORTISOL 212
I. Introduction 213
II. Circulating Levels of Cortisol in the Fetus 213
III. Sources of Cortisol in the Fetal Circulation 217
IV. Fate of Fetal Cortisol 228
V. Significance of Cortisol in the Fetus 233
VI. Summary 237
References 238
CHAPTER 9. SEXUAL DIFFERENTIATION: NORMAL AND ABNORMAL 246
I. Embryology of Sexual Differentiation 247
II. Determinants of Phenotypic Differentiation 253
III. Genetic Control of Sexual Differentiation 261
IV. Sexual Differentiation of the Brain 262
V. Male Pseudohermaphroditism 264
VI. XX Males and True Hermaphroditism 301
VII. Female Pseudohermaphroditism 304
References 311
CHAPTER 10. METABOLIC ERRORS OFADRENAL STEROIDOGENESIS 324
I. Introduction 325
II. Steroidogenesis and Enzymatic Conversions of Adrenal Steroid Hormones 325
III. Fetal Sexual Development 330
IV. Enzyme Defects in Congenital Adrenal Hyperplasia 330
V. The Zona Fasciculata and Zona Glomerulosa as Separate Glands 338
VI. Treatment of Congenital Adrenal Hyperplasia 341
VII. Genetics of Congenital Adrenal Hyperplasia 344
VIII. Prenatal Diagnosis of Congenital Adrenal Hyperplasia 367
IX. Summary 367
Acknowledgments 368
References 368
INDEX 374
In Vitro Fertilization
Alan Trounson, DEPARTMENT OF OBSTETRICS AND GYNAECOLOGY, MONASH UNIVERSITY, QUEEN VICTORIA MEDICAL CENTRE, MELBOURNE, AUSTRALIA
Publisher Summary
Successful in vitro fertilization (IVF) may be approached by either of two methods that differ substantially in concept. One method of obtaining normal oocytes for IVF is to rely on the precise determination of periovular changes to predict the exact time of ovulation in the natural or spontaneous ovulatory cycle. This approach necessitates complete reliance on a method for determining the onset of the preovulatory luteinizing hormone surge and requires personnel and facilities to be available 24 hours a day to recover oocytes at the appropriate time. The difficulties of this approach reside in the variable and often unpredictable rise in LH, the absolute necessity of recovering the single mature oocyte in each ovulatory cycle, and the inefficient use of available facilities and personnel. The alternative approach is to control the ovulatory response by the judicious use of clomiphene citrate or exogenous gonadotropins to initiate follicle growth and the administration of human chorionic gonadotropin or gonadotropin releasing hormone to control the time of the final stages of oocyte maturation. This method has many advantages when compared to IVF in the natural cycle.
I The Natural Ovulatory Cycle and IVF
A The Statistical Prediction of the day of Ovulation
B Urinary or Plasma Estrogen Levels
II The Stimulated or Controlled Ovulatory Cycle
B Hormonal and Follicular Responses to Clomiphene and Exogenous Gonadotropins
IV The Technique of in Vitro Fertilization 63
C Insemination of Oocytes and Culture of Embryos in Vitro 65
Successful in vitro fertilization (IVF) may be approached by either of two methods which differ substantially in concept. One method of obtaining normal oocytes for IVF is to rely on the precise determination of periovular changes to predict the exact time of ovulation in the natural or spontaneous ovulatory cycle. This approach necessitates complete reliance on a method for determining the onset of the preovulatory luteinizing hormone (LH) surge and requires personnel and facilities to be available 24 hours a day to recover oocytes at the appropriate time. This approach has been shown to result in the birth of normal babies (Edwards et al., 1980a; Lopata et al., 1980a). The difficulties of this approach reside in the variable and often unpredictable rise in LH, the absolute necessity of recovering the single mature oocyte each ovulatory cycle, and the inefficient use of available facilities and personnel.
The alternative approach is to control the ovulatory response by the judicious use of clomiphene citrate or exogenous gonadotropins to initiate follicle growth and the administration of human chorionic gonadotropin (hCG) or gonadotropin releasing hormone (GnRH) to control the time of the final stages of oocyte maturation. This method has also been shown to be successful for IVF (Trounson et al., 1981a) and has many advantages when compared to IVF in the natural cycle. The procedure of controlled IVF, in particular, requires a full understanding of the basic principles of the human ovulatory cycle. This may only be apparent when difficulties are encountered by new groups following recipes for successful IVF of the established clinics. Even though many of the exact conditions required to obtain maximum success of IVF are yet to be elucidated, there is now substantial data available to indicate the general conditions and procedures required for success. A description of these conditions may provide a more stable basis for the continued development and application of IVF for treatment of human infertility.
I The Natural Ovulatory Cycle and IVF
The variability of the time of ovulation for any woman during the menstrual cycle has been often described and may be clearly demonstrated by the data reported by Mcintosh et al. (1980). In their study, the time of the LH surge was recorded for patients attending an artificial insemination by donor semen (AID) service. Most of the husbands of these patients were azoospermic, so that the majority of the women could be considered to have normal fertility and ovulated regularly. They were able to compute the 95% confidence limits for the day of ovulation from the mean menstrual cycle length and sample standard deviation. The validity of their predictions were confirmed by comparing the predicted time of ovulation with subsequent determinations of the day of the peripheral plasma LH surge. When examining these data it is apparent that the variation in the day of ovulation is considerable and if it is necessary to predict ovulation within 2 to 6 hours for oocyte recovery, precise tests and considerable patience are necessary.
During the follicular phase of the ovulatory cycle a number of antral follicles of between 0.8 and 1.5 cm in diameter can be detected in the growth phase by ultrasound but it is unusual to observe more than one follicle larger than 1.7 cm within 3 days of ovulation. It is not known when the final commitment is made as to which follicle is destined for the final growth phase and ovulation in the human. Even though the growth of the ovulating follicle appears to be continuous, it is not known if the increase in follicular diameter is constant or characterized by periods of expansion. Disturbance to constant follicular growth and expansion would result in difficulties for the use of ultrasound, as the primary monitor for assessing the approach of ovulation. Furthermore, the final size of the follicle at the time of ovulation may vary between patients and between ovulatory cycles. This would appear to be the case in studies with our own patients. The system for monitoring approaching ovulation should not rely on a single parameter, but rather a combination of a number of indicators.
A The Statistical Prediction of the Day of Ovulation
The 95% confidence limits for the day of the expected LH rise from previous records of menstrual cycle length is calculated (see Mcintosh et al., 1980). The variation in menstrual cycle length appears to be composed of 80% variation in follicular phase length and 20% variation in the length of the luteal phase. This information can assist the organization of other tests for approaching ovulation and to indicate the time for hospitalization or concentrated sampling for the detection of the LH surge.
B Urinary or Plasma Estrogen Levels
Estimation of ovarian follicular estrogen secretion provides a useful indication of the final growth phase of the follicle. Total urinary estrogens assayed daily in 24-hour urine collections show the well-documented increase 3 to 4 days before preovulatory LH release (Brown et al., 1968). Failure of total urinary estrogens to exceed 10 µg/24 hours, indicates failure of normal follicular growth. When rising estrogen excretion rates are between 30 and 60 μg/24 hours, LH release would be expected to occur within the next 2 to 3 days. Utilization of daily estrogen excretion rates has been an integral component of IVF protocols for some time (Lopata et al., 1978; Edwards et al., 1980a) and has been used in conjunction with endogenous LH determinations for successful IVF in the natural ovulatory cycle (Edwards et al., 1980a; Lopata et al., 1980a).
The use of rapid radioimmunoassays for peripheral plasma estradiol-17β (Mikhail et al., 1970; Tredway et al., 1974; Dobson et al., 1975) is an attractive alternative to the measurement of total urinary estrogens. Depending upon the...
Erscheint lt. Verlag | 22.10.2013 |
---|---|
Sprache | englisch |
Themenwelt | Medizin / Pharmazie |
ISBN-10 | 1-4832-1737-X / 148321737X |
ISBN-13 | 978-1-4832-1737-6 / 9781483217376 |
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