Martini / James Fetal Endocrinology and Metabolism

Current Topics in Experimental Endocrinology, Vol. 5
1. Auflage 2013
ISBN: 978-1-4832-1737-6
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 378 Seiten

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.

Autoren/Hrsg.

Martini, L.

James, V. H. T.

Inhaltsverzeichnis

1;Front Cover;1
2;Fetal Endocrinology and Metabolism;4
3;Copyright Page;5
4;Table of Contents;6
5;CONTRIBUTORS;10
6;PREFACE;12
7;CHAPTER 1. THE FETAL NEUROENDOCRINE AXIS;16
7.1;I. Introduction;16
7.2;II. The Development of the Hypothalamus and Adenohypophysis;18
7.3;III. The Secretion and Function of Fetal Adenohypophyseal Hormones (see Fig. 1);22
7.4;IV. Autonomy of the Fetal Neuroendocrine Unit;43
7.5;Acknowledgments;45
7.6;References;46
8;CHAPTER 2. IN VITRO FERTILIZATION;58
8.1;I. The Natural Ovulatory Cycle and IVF;59
8.2;II. The Stimulated or Controlled Ovulatory Cycle;69
8.3;III. Maturation of the Oocyte;76
8.4;IV. The Technique of in Vitro Fertilization;78
8.5;V. The Use of IVF in Male and Idiopathic Infertility;85
8.6;References;86
9;CHAPTER 3. FACTORS CONTROLLING PLACENTAL ENDOCRINE FUNCTION IN DOMESTIC ANIMALS;90
9.1;I. Introduction;90
9.2;II. Control of Placental Steroid Secretion by Fetal Cortisol in Domestic Animals;92
9.3;III. Control of Secretion of Placental Lactogens;103
9.4;IV. Effects of /3-Catecholaminergic Drugs on the Placenta;105
9.5;V. Conclusions;106
9.6;References;108
10;CHAPTER 4. THE FETAL THYROID;112
10.1;I. Introduction;112
10.2;II. The Choice of Preparation;113
10.3;III. The Morphological and Secretory Development of the Gland;114
10.4;IV. The Placental Barrier;117
10.5;V. The Role of the Thyroid in Fetal Development;119
10.6;VI. Fetal Thyroid Hormone Kinetics;121
10.7;VII. Perinatal Thyroid Hormone Concentrations;124
10.8;VIII. Conclusion;128
10.9;Acknowledgment;129
10.10;References;129
11;CHAPTER 5. CARBOHYDRATE METABOLISM;132
11.1;I. Introduction;133
11.2;II. Maternal Hormonal and Metabolic Adaptations;133
11.3;III. Early Embryonic Development;139
11.4;IV. Placental Transfer of Carbohydrates;141
11.5;V. Fetal Hormones and Carbohydrate Utilization;148
11.6;VI. Fetal Metabolic Pathways;152
11.7;VII. Summary;153
11.8;References;153
12;CHAPTER 6. REGULATION OF PARTITION OF PROTEIN DURING PREGNANCY;160
12.1;I. Introduction;161
12.2;II. Placental Protein;161
12.3;III. Fetal Protein;166
12.4;IV. Free Amino Acid Pools;174
12.5;V. Maternal Protein;181
12.6;References;188
13;CHAPTER 7. MINERAL NEEDS OF THE FETUS;192
13.1;I. Introduction;193
13.2;II. Calcium, Phosphate, Magnesium;193
13.3;III. Parathyroid Hormone (PTH);194
13.4;IV. Vitamin D;196
13.5;V. Calcitonin;202
13.6;VI. Hormone Interrelations;206
13.7;VII. Conclusion;208
13.8;References;208
14;CHAPTER 8. FETAL METABOLISM OF CORTISOL;212
14.1;I. Introduction;213
14.2;II. Circulating Levels of Cortisol in the Fetus;213
14.3;III. Sources of Cortisol in the Fetal Circulation;217
14.4;IV. Fate of Fetal Cortisol;228
14.5;V. Significance of Cortisol in the Fetus;233
14.6;VI. Summary;237
14.7;References;238
15;CHAPTER 9. SEXUAL DIFFERENTIATION: NORMAL AND ABNORMAL;246
15.1;I. Embryology of Sexual Differentiation;247
15.2;II. Determinants of Phenotypic Differentiation;253
15.3;III. Genetic Control of Sexual Differentiation;261
15.4;IV. Sexual Differentiation of the Brain;262
15.5;V. Male Pseudohermaphroditism;264
15.6;VI. XX Males and True Hermaphroditism;301
15.7;VII. Female Pseudohermaphroditism;304
15.8;References;311
16;CHAPTER 10. METABOLIC ERRORS OFADRENAL STEROIDOGENESIS;324
16.1;I. Introduction;325
16.2;II. Steroidogenesis and Enzymatic Conversions of Adrenal Steroid Hormones;325
16.3;III. Fetal Sexual Development;330
16.4;IV. Enzyme Defects in Congenital Adrenal Hyperplasia;330
16.5;V. The Zona Fasciculata and Zona Glomerulosa as Separate Glands;338
16.6;VI. Treatment of Congenital Adrenal Hyperplasia;341
16.7;VII. Genetics of Congenital Adrenal Hyperplasia;344
16.8;VIII. Prenatal Diagnosis of Congenital Adrenal Hyperplasia;367
16.9;IX. Summary;367
16.10;Acknowledgments;368
16.11;References;368
17;INDEX;374

Leseproben

Fertilization

Alan Trounson,     DEPARTMENT OF OBSTETRICS AND GYNAECOLOGY, MONASH UNIVERSITY, QUEEN VICTORIA MEDICAL CENTRE, MELBOURNE, AUSTRALIA

Publisher Summary

Successful 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

C Cervical Mucus Score

D Ultrasonic Determination of Follicular Size

E Detection of the LH Surge

F Plasma Progesterone or Urinary Pregnanediol

II The Stimulated or Controlled Ovulatory Cycle

A Theoretical Considerations

B Hormonal and Follicular Responses to Clomiphene and Exogenous Gonadotropins

C Monitoring the Stimulated Ovulatory Cycle.

D The Time of hCG Injection

E The Time of Laparoscopy

III Maturation of the Oocyte

IV The Technique of Fertilization 63

A Patient Management

B Oocyte Recovery

C Insemination of Oocytes and Culture of Embryos 65

D Embryo Transfer

E Treatment of IVF Patients during Pregnancy

F Future Developments in IVF

V The Use of IVF in Male and Idiopathic Infertility

References

Successful 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 1980a; Lopata 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 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 (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 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 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 1978; Edwards 1980a) and has been used in conjunction with endogenous LH determinations for successful IVF in the natural ovulatory cycle (Edwards 1980a; Lopata 1980a).

The use of rapid radioimmunoassays for peripheral plasma estradiol-17ß (Mikhail 1970; Tredway 1974; Dobson 1975) is an attractive alternative to the measurement of total urinary estrogens. Depending upon the...