OBJECTIVE

We sought to evaluate hypoestrogenemia of hypothalamic origin and its association with angiographic coronary artery disease (CAD) in premenopausal women.

BACKGROUND

Coronary artery disease in premenopausal women appears to have a particularly poor prognosis. Primate animal data suggest that premenopausal CAD is strongly determined by psychosocial stress-induced central disruption of ovulatory cycling and resulting hypoestrogenemia.

METHODS

We assessed reproductive hormone blood levels and angiographic CAD using core laboratories in 95 premenopausal women with coronary risk factors who were enrolled in the National Heart, Lung, and Blood Institute-sponsored Women's Ischemia Syndrome Evaluation and were undergoing coronary angiography for evaluation for suspected ischemia.

RESULTS

Premenopausal women with angiographic CAD (n = 13) had significantly lower estradiol, bioavailable estradiol, and follicle-stimulating hormone (FSH) (all p < 0.05) than women without angiographic CAD (n = 82), even after controlling for age. Hypoestrogenemia of hypothalamic origin, defined as estradiol <184 pmol/l (50 pg/ml), FSH <10 IU/l, and luteinizing hormone <10 IU/l, was significantly more prevalent among the women with CAD than those without CAD (9/13 [69%] vs. 24/82 [29%], respectively, p = 0.01). Hypoestrogenemia of hypothalamic origin was the most powerful predictor of angiographic CAD in a multivariate model (odds ratio [OR] 7.4 [confidence interval (CI) 1.7 to 33.3], p = 0.008). Anxiolytic/sedative/hypnotic and antidepressant medication use were independent predictors of hypoestrogenemia of hypothalamic origin in a multivariate model (OR 4.6 [CI 1.3 to 15.7], p = 0.02, OR 0.10 [CI 0.01 to 0.92], p = 0.04, respectively).

CONCLUSIONS

Among premenopausal women undergoing coronary angiography for suspected myocardial ischemia, disruption of ovulatory cycling characterized by hypoestrogenemia of hypothalamic origin appears to be associated with angiographic CAD.

Total and unbound testosterone and Delta(4)-androstenedione have been determined in 104 cord blood samples. The same sexual steroids and pituitary gonadotropins have been measured in 46 normal male infants aged 27-348 days and 34 normal female infants aged 19-332 days. In cord blood of female neonates mean total and unbound testosterone was 29.6+/-7.5 and 0.89+/-0.4 ng/100 ml, respectively (mean+/-1 SD); Delta(4)-androstenedione was 93+/-38 ng/100 ml. In male neonates mean plasma total and unbound testosterone was 38.9+/-10.8 and 1.12+/-0.4 ng/100 ml; Delta(4)-androstenedione was 85+/-27 ng/100 ml. In female infants testosterone concentrations remained constant during the 1st yr of life with a mean concentration of 7+/-3 ng/100 ml. Mean unbound testosterone and Delta(4)-androstenedione concentrations were 0.05+/-0.03 and 16.7+/-8.3 ng/100 ml, respectively. Mean plasma levels of follicle-stimulating hormone and luteinizing hormone were 8.7+/-3.3 and 12.9+/-7.7 mU/ml. In male infants mean plasma total testosterone concentration increased to 208+/-68 ng/100 ml from birth to 1-3 mo of age, decreasing thereafter to 95+/-53 ng/100 ml at 3-5 mo, 23.2+/-18 ng/100 ml at 5-7 mo, and reached prepubertal levels (6.6+/-4.6 ng/100 ml) at 7-12 mo. Mean unbound testosterone concentration plateaued from birth to 1-3 mo of age (1.3+/-0.2 ng/100 ml) decreasing to prepubertal values very rapidly. Mean Delta(4)-androstenedione concentration, although progressively decreasing during the 1st yr of life to 11.7+/-4.5 ng/100 ml, was higher than in the female at 1-3 mo of life (34+/-11 ng/100 ml). Mean plasma level of follicle-stimulating hormone was 6.7+/-2.9 mU/ml, and that of luteinizing hormone was 19.7+/-13.5 mU/ml, significantly higher than in the female. There was no correlation between gonadotropin and age or testosterone. The present data demonstrate that the testes are active during the first natal period. It is tempting to correlate this phenomenon to a progressive maturation of the hypothalamo-pituitary-gonadal axis. It is possible that the surge in testosterone occurring the first 3 mo could play a role in the future life pattern of the male human being.

In most cases, pharmacologic strategies to treat genetic muscle disorders and certain acquired disorders, such as sporadic inclusion body myositis, have produced modest clinical benefits. In these conditions, inhibition of the myostatin pathway represents an alternative strategy to improve functional outcomes. Preclinical data that support this approach clearly demonstrate the potential for blocking the myostatin pathway. Follistatin has emerged as a powerful antagonist of myostatin that can increase muscle mass and strength. Follistatin was first isolated from the ovary and is known to suppress follicle-stimulating hormone. This raises concerns for potential adverse effects on the hypothalamic-pituitary-gonadal axis and possible reproductive capabilities. In this review we demonstrate a strategy to bypass off-target effects using an alternatively spliced cDNA of follistatin (FS344) delivered by adeno-associated virus (AAV) to muscle. The transgene product is a peptide of 315 amino acids that is secreted from the muscle and circulates in the serum, thus avoiding cell-surface binding sites. Using this approach our translational studies show increased muscle size and strength in species ranging from mice to monkeys. Adverse effects are avoided, and no organ system pathology or change in reproductive capabilities has been seen. These findings provide the impetus to move toward gene therapy clinical trials with delivery of AAV-FS344 to increase size and function of muscle in patients with neuromuscular disease.

The developmental requirements of ovarian follicles are dependent on the maturation stage of the follicle; in particular, elegant studies with genetic models have indicated that FSH is required for antral, but not preantral, follicle growth and maturation. To elucidate further the role of FSH and other regulatory molecules in preantral follicle development, in vitro culture systems are needed. We employed a biomaterials-based approach to follicle culture, in which follicles were encapsulated within matrices that were tailored to the specific developmental needs of the follicle. This three-dimensional system was used to examine the impact of increasing doses of FSH on follicle development for two-layered secondary (100-130 microm; two layers of granulosa cells surrounding the oocyte) and multilayered secondary (150-180 microm, several layers of granulosa cells surrounding the oocyte) follicles isolated from mice. Two-layered secondary follicles were FSH responsive when cultured in alginate-collagen I matrices, exhibiting FSH dose-dependent increases in follicle growth, lactate production, and steroid secretion. Multilayered secondary follicles were FSH dependent, with follicle survival, growth, steroid secretion, metabolism, and oocyte maturation all regulated by FSH. However, doses greater than 25 mIU/ml of FSH negatively impacted multilayered secondary follicle development (reduced follicle survival). The present results indicate that the hormonal and environmental needs of the follicular complex change during the maturation process. The culture system can be adapted to each stage of development, which will be especially critical for translation to human follicles that have a longer developmental period.

OBJECTIVE

To investigate the association between urinary hormone levels and migraine, with particular reference to rising and falling levels of estrogen across the menstrual cycle in women with menstrual and menstrually related migraine.

METHODS

Women with regular menstrual cycles, who were not using hormonal contraception or treatments and who experienced between one and four migraine attacks per month, one of which regularly occurred on or between days 1 +/- 2 of menstruation, were studied for three cycles. Women used a fertility monitor to identify ovulation, conducting a test each day as requested by the monitor, using a sample of early morning urine. Urine samples were collected daily for assay of estrone-3-glucuronide, pregnanediol 3-glucuronide, follicle-stimulating hormone, and luteinizing hormone. All women kept a daily migraine diary and continued their usual treatment for migraine.

RESULTS

Of 40 women recruited, data from 38 women were available for analysis. Compared with the expected number of attacks, there was a significantly higher number of migraine attacks during the late luteal/early follicular phase of falling estrogen and lower number of attacks during rising phases of estrogen.

CONCLUSIONS

These findings confirm a relationship between migraine and changing levels of estrogen, supporting the hypothesis of perimenstrual but not postovulatory estrogen "withdrawal" migraine. In addition, rising levels of estrogen appear to offer some protection against migraine.

A study was conducted to form a unified hypothesis regarding the gonadotropin-related mechanisms that underlie alterations in the male reproductive system in individuals with diabetes. Streptozotocin-induced diabetes resulted in reduced fertility, prolificacy, and libido. Testes showed a marked decrease in the number and function of Leydig cells, the latter manifested as changes in the expression of biochemical markers, including the GLUT-3 hexose transporter, c-kit, insulin-like growth factor I (IGF-I), androgen receptors, and overall tyrosine phosphorylation, as assessed by Western blot and immunocytochemical analyses. The expression of c-kit, IGF-I, insulin, and follicle-stimulating hormone (FSH) receptors in the seminiferous tubules was also affected. Serum levels of luteinizing hormone (LH), FSH, and testosterone significantly decreased. There was a significant (P <.05) correlation between the serum levels of insulin and FSH. No significant correlation was found between the serum levels of insulin or glucose and LH. On the basis of our results, we conclude that, in insulin-dependent diabetes, 1) Leydig cell function and testosterone production decrease because of the absence of the stimulatory effect of insulin on these cells and an insulin-dependent decrease in FSH, which, in turn, reduces LH levels; and 2) sperm output and fertility are reduced because of a decrease in FSH caused by a reduction in insulin.

From a longitudinal prospective study, 160 women with spontaneous menopause and without steroid medication were followed during the transition from pre- to postmenopause. After 12 years 152 women were still participating in the study. Blood samples were drawn every 6 months until 1 year after the menopause and every 12 months thereafter. Measurements of bone mineral density (BMD) on the forearm were performed every second year. All women routinely completed a questionnaire concerning symptoms frequently attributed to the climacteric period. All data were grouped around the onset of the menopause, thereby allowing longitudinal evaluation of the changes in the variables from the premenopausal to the postmenopausal period. The beginning of the perimenopausal period was characterized by transitory elevations of follicle-stimulating hormone (FSH). A significant increase in serum levels of gonadotropins was observed for both FSH and luteinizing hormone (LH) from about 5 years before the menopause. Within the 6 month period around the menopause there was a further increase which culminated within the first postmenopausal year for LH and 2-3 years postmenopause for FSH. Thereafter, a continuous decrease in LH occurred over the following 8 years. With respect to FSH, there was a slight decline starting about 4 years postmenopause. During the premenopausal period an increasing frequency of inadequate luteal function or anovulation occurred and, in the postmenopausal years, the serum levels of progesterone (P) were invariably low. Gradually, the ratio between estrone (E1) and 17-beta-estradiol (E2) increased, reflecting the declining follicular steroidogenesis. A marked decrease in estrogen levels occurred during the 6 month period around the menopause, most pronounced in E2. During the next 3 years, the levels of E2 and E1 showed an essentially parallel, moderate decline. Around the menopause, serum levels of testosterone (T), delta 4-androstenedione (A) and sex hormone-binding globulin (SHBG) showed small but significant decreases. From about 3 years postmenopause, the levels were relatively constant over the following 5 years. A decrease in BMD was observed in the postmenopause, and from about 3 years postmenopause, estradiol correlated positively with BMD. Before, as well as after the menopause, body mass index (BMI) showed an inverse correlation with SHBG. Postmenopausal androstenedione correlated positively with E1, E2 and T. BMI correlated positively with E1 and E2. The concentrations of the free fraction of E2 and T are dependent on the levels of SHBG, which in turn has a negative correlation with BMI. The impact of this will influence the severity of symptoms, the degree of bone loss and the need for supplementary therapy.

Declining estrogen production after menopause causes osteoporosis in which the resorption of bone exceeds the increase in bone formation. We recently found that mice deficient in the beta-subunit of follicle-stimulating hormone (FSHbeta) are protected from bone loss despite severe estrogen deficiency. Here we show that FSHbeta-deficient mice have lowered TNFalpha levels. However, TNFalpha-deficient mice are resistant to hypogonadal bone loss despite having elevated FSH, suggesting that TNFalpha is critical to the effect of FSH on bone mass. We find that FSH directly stimulates TNFalpha production from bone marrow granulocytes and macrophages. We also explore how TNFalpha up-regulation induces bone loss. By modeling the known actions of TNFalpha, we attribute the high-turnover bone loss to an expanded osteoclast precursor pool, together with enhanced osteoblast formation. TNFalpha inhibits osteoblastogenesis in the presence of ascorbic acid in culture medium, but in its absence this effect becomes stimulatory; thus, ascorbic acid reverses the true action of TNFalpha. Likewise, ascorbic acid blunts the effects of TNFalpha in stimulating osteoclast formation. We propose that hypogonadal bone loss is caused, at least in part, by enhanced FSH secretion, which in turn increases TNFalpha production to expand the number of bone marrow osteoclast precursors. Ascorbic acid may prevent FSH-induced hypogonadal bone loss by modulating the catabolic actions of TNFalpha.

There is increasing interest in the possibility that disruption of normal circadian rhythm may increase the risk of developing cancer. Persons who engage in nightshift work may exhibit altered nighttime melatonin levels and reproductive hormone profiles that could increase the risk of hormone-related diseases, including breast cancer. Epidemiologic studies are now beginning to emerge suggesting that women who work at night, and who experience sleep deprivation, circadian disruption, and exposure to light-at-night are at an increased risk of breast cancer, and possibly colorectal cancer as well. Several studies have been conducted in Seattle recently to investigate the effects of factors that can disrupt circadian rhythm and alter normal nocturnal production of melatonin and reproductive hormones of relevance to breast cancer etiology. Studies completed to date have found: (1) an increased risk of breast cancer associated with indicators of exposure to light-at-night and night shift work; and (2) decreased nocturnal urinary levels of 6-sulphatoxymelatonin associated with exposure to 60-Hz magnetic fields in the bedroom the same night, and a number of other factors including hours of daylight, season, alcohol consumption and body mass index. Recently completed is an experimental crossover study designed to investigate whether exposure to a 60-Hz magnetic field under controlled conditions in the home sleeping environment is associated with a decrease in nocturnal urinary concentration of 6-sulphatoxymelatonin, and an increase in the urinary concentration of luteinizing hormone, follicle stimulating hormone, and estradiol in a sample of healthy women of reproductive age. Presently underway is a study to determine whether working at night is associated with decreased levels of urinary 6-sulphatoxymelatonin, and increased urinary concentrations of the reproductive hormones listed above in a sample of healthy women of reproductive age, and to elucidate characteristics of sleep among night shift workers that are related to the hormone patterns identified. A proposal is under review to extend these studies to a sample of healthy men to investigate whether working at night is associated with decreased levels of urinary 6-sulphatoxymelatonin, and increased concentrations of urinary cortisol and cortisone, urinary levels of a number of androgen metabolites, and serum concentrations of a number of reproductive hormones. Secondarily, the proposed study will elucidate characteristics of sleep among night shift workers that are related to the hormone patterns identified, as well as investigate whether polymorphisms of the genes thought to regulate the human circadian clock are associated with the ability to adapt to night shift work. It is anticipated that collectively these studies will enhance our understanding of the role of circadian disruption in the etiology of cancer.

The crystal structure of a betaThr26Ala mutant of human follicle-stimulating hormone (hFSH) has been determined to 3.0 A resolution. The hFSH mutant was expressed in baculovirus-infected Hi5 insect cells and purified by affinity chromatography, using a betahFSH-specific monoclonal antibody. The betaThr26Ala mutation results in elimination of the betaAsn24 glycosylation site, yielding protein more suitable for crystallization without affecting the receptor binding and signal transduction activity of the glycohormone. The crystal structure has two independent hFSH molecules in the asymmetric unit and a solvent content of about 80%. The alpha- and betasubunits of hFSH have similar folds, consisting of central cystine-knot motifs from which three beta-hairpins extend. The two subunits associate very tightly in a head-to-tail arrangement, forming an elongated, slightly curved structure, similar to that of human chorionic gonadotropin (hCG). The hFSH heterodimers differ only in the conformations of the amino and carboxy termini and the second loop of the beta-subunit (L2beta). Detailed comparison of the structures of hFSH and hCG reveals several differences in the beta-subunits that may be important with respect to receptor binding specificity or signal transduction. These differences include conformational changes and/or differential distributions of polar or charged residues in loops L3beta (hFSH residues 62-73), the cystine noose, or determinant loop (residues 87-94), and the carboxy-terminal loop (residues 94-104). An additional interesting feature of the hFSH structure is an extensive hydrophobic patch in the area formed by loops alphaL1, alphaL3, and betaL2. Glycosylation at alphaAsn52 is well known to be required for full signal transduction activity and heterodimer stability. The structure reveals an intersubunit hydrogen bonding interaction between this carbohydrate and betaTyr58, an indication of a mechanism by which the carbohydrate may stabilize the heterodimer.

BACKGROUND

Individualization of controlled ovarian stimulation (COS) for assisted conception is complicated by variable ovarian response to follicle stimulating hormone. We hypothesized that anti-Müllerian hormone (AMH), a predictor of oocyte yield, may facilitate treatment strategies for women undergoing COS, to optimize safety and clinical pregnancy rates.

METHODS

Prospective cohort study of 538 patients in two centres with differential COS strategies based on a centralized AMH measurement.

RESULTS

AMH was associated with oocyte yield after ovarian stimulation in both centres, and a 'reduced' AMH (1 to <5 pmol/l) was associated with a reduced clinical pregnancy rate. Women with a 'normal' AMH (5 to <15 pmol/l) treated with a long GnRH-agonist protocol (both centres) showed a low incidence of excess response (0%) and poor response (0%). In women with 'high' AMH (>15 pmol/l), the antagonist protocol eliminated the need for complete cryopreservation of embryos due to excess response (P < 0.001) and showed a higher fresh cycle clinical pregnancy rate than agonist cycles [OR 4.40 (95% CI 1.95-9.93), P < 0.001].

CONCLUSIONS

The use of circulating AMH to individualize treatment strategies for COS may result in reduced clinical risk, optimized treatment burden and maintained pregnancy rates, and is worthy of prospective randomized examination.

OBJECTIVE

The aim of this study was to estimate associations of obesity with reproductive hormone levels as women progress from premenopausal to postmenopausal status.

METHODS

This was a longitudinal study conducted in the population-based Penn Ovarian Aging Cohort (N = 436). At cohort enrollment, the women were premenopausal, ages 35 to 47 years, with equal numbers of African Americans and whites. Anthropometric measures, menopause status, and reproductive hormone measures were evaluated for 12 years. Associations of the anthropometric measures with estradiol, follicle-stimulating hormone, and inhibin B in the menopausal transition were estimated using generalized linear regression models for repeated measures.

RESULTS

Associations between obesity and hormone levels differed by menopause status as indicated by significant interactions between each hormone and menopausal stage. Premenopausal obese and overweight women had significantly lower estradiol levels compared with nonobese women, independent of age, race, and smoking (obese: 32.8 pg/mL [95% CI, 30.6-35.2] vs nonobese: 39.8 pg/mL [95% CI, 37.0-42.8], P < 0.001). The associations reversed postmenopause, with obese women having the highest estradiol levels (obese: 20.6 pg/mL [95% CI, 17.2-24.7] vs nonobese: 12.2 pg/mL [95% CI, 10.1-14.8], P < 0.001). Inhibin B levels were significantly lower in premenopausal obese compared with nonobese women but reversed in the late transition stage. Follicle-stimulating hormone levels were lowest in postmenopausal obese compared with nonobese women (P < 0.001). Measures of waist circumference (central adiposity) and waist-to-hip ratio paralleled the body mass index results.

CONCLUSIONS

Obesity is an important factor in hormone dynamics independent of age, race, and smoking in midlife women, although the mechanisms remain unclear.

The role of insulin in the regulation of basal and gonadotropin-releasing hormone (GnRH)-stimulated release of LH and FSH was investigated in vitro using primary cultures of rat anterior pituitary cells from adult ovariectomized rats. Anterior pituitary cells were incubated for 2 days in the presence or absence of insulin in a serum-free medium. At the end of the insulin treatment, the cells were washed and reincubated in the presence or absence of GnRH, and the LH and FSH released into the medium were measured by RIA. Treatment with insulin (1.0 microgram/ml) for 2 days resulted in significant increases in both the basal and the maximal release of LH and FSH, as well as a 3.2- and 6.3-fold decrease in the ED50 values for GnRH in terms of LH and FSH release, respectively. Treatment with increasing concentrations (0.1-10,000 ng/ml) of insulin, led to a dose-dependent increase in the GnRH (3 X 10(-10) M)-stimulated release of both LH and FSH. This effect of insulin was significant (P less than 0.05) at a physiological concentration of 1 ng/ml (24 microU/ml) with an ED50 value of 40 ng/ml. Increasing duration of exposure to insulin resulted in time-dependent increases in the GnRH (3 X 10(-10) M)-stimulated release of LH, becoming significant at 24 h with maximal enhancement observed by 48 h. The effect of insulin was specific; epidermal or fibroblast growth factor did not enhance LH release. The augmenting effect of insulin was not associated with cellular proliferation or an overall change in protein or LH synthesis. Furthermore, the effect of insulin was independent of the ambient glucose concentration. Insulin was, however, without effect on gonadotrophs cultured in a serum-supplemented medium. Our findings suggest that the gonadotroph constitutes a target cell of insulin and that insulin may act directly on the anterior pituitary in the regulation of gonadotropin release.

Estrogens profoundly influence the physiology and pathology of reproductive and other tissues. Consequently, emphasis has been placed on delineating the mechanisms underlying regulation of estrogen levels. Circulating levels of estradiol in women are controlled by follicle-stimulating hormone (FSH), which regulates transcription of the aromatase gene (CYP19A1) in ovarian granulosa cells. Previous studies have focused on two downstream effectors of the FSH signal, cAMP and the orphan nuclear receptor steroidogenic factor-1 (NR5A1). In this report, we present evidence for beta-catenin (CTNNB1) as an essential transcriptional regulator of CYP19A1. FSH induction of select steroidogenic enzyme mRNAs, including Cyp19a1, is enhanced by beta-catenin. Additionally, beta-catenin is present in transcription complexes assembled on the endogenous gonad-specific CYP19A1 promoter, as evidenced by chromatin immunoprecipitation assays. Transient expression and RNAi studies demonstrate that FSH- and cAMP-dependent regulation of this promoter is sensitive to alterations in the level of beta-catenin. The stimulatory effect of beta-catenin is mediated through functional interactions with steroidogenic factor-1 that involve four acidic residues within its ligand-binding domain, mutation of which attenuates FSH/cAMP-induced Cyp19a1 mRNA accumulation. Together, these data demonstrate that beta-catenin is essential for FSH/cAMP-regulated gene expression in the ovary, identifying a central and previously unappreciated role for beta-catenin in estrogen biosynthesis, and a potential broader role in other aspects of follicular maturation.

Middle-aged men with abdominal obesity were treated in a double-blind study with moderate doses of transdermal preparations of testosterone (T), dihydrotestosterone (DHT), or placebo. This resulted in moderately elevated T concentrations and marked decreases in follicle stimulating and luteinizing hormones in the group treated with T, while the DHT group showed elevated DHT, markedly lower T values, and less diminution of gonadotropin concentrations. In the group treated with T visceral fat mass decreased (measured by computerized tomography) without significant changes in other depot fat regions. Lean body mass did not change. In the group treated with T, glucose disposal rate, measured with the euglycemic hyperinsulinemic clamp method, was markedly augmented. Plasma triglycerides, cholesterol, and fasting blood glucose concentrations as well as diastolic blood pressure decreased. There were no such changes in the DHT or placebo treatment groups. The men treated with T reported increased well-being and energy. In none of the groups did prostate volume, specific prostate antigen concentration, genito-urinary history, or urinary flow measurement change. It is suggested that supplementation of abdominal obese men with moderate doses of T might have several beneficial effects.

The purpose of this study was to assess pituitary gonadotropins and free testosterone levels in a larger cohort of men with Alzheimer's disease (AD, n=112) and age-matched controls (n=98) from the Oxford Project to Investigate Memory and Ageing (OPTIMA). We measured gonadotropins (follicle stimulating hormone, FSH, and luteinizing hormone, LH), sex hormone binding globulin (SHBG, which determines the amount of free testosterone) and total testosterone (TT) using enzyme immunoassays. AD cases had significantly higher LH and FSH and lower free testosterone levels. LH, FSH and SHBG all increased with age, while free testosterone decreased. Low free testosterone was an independent predictor for AD. Its variance was overall explained by high SHBG, low TT, high LH, an older age and low body mass index (BMI). In controls, low thyroid stimulating hormone levels were also associated with low free testosterone. Elderly AD cases had raised levels of gonadotropins. This response may be an attempt to normalize low free testosterone levels. In non-demented participants, subclinical hyperthyroid disease (a risk factor for AD) which can result in higher SHBG levels, was associated with low free testosterone. Lowering SHBG and/or screening for subclinical thyroid disease may prevent cognitive decline and/or wasting in men at risk for AD.

When administered in overtly toxic doses to postweanling male rats, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces adverse effects on the reproductive system including a decrease in spermatogenesis. Because the male reproductive system may be particularly susceptible to toxic insult during the perinatal period, the effects of in utero and lactational TCDD exposure on its development were examined. Male rats born to dams given TCDD (0.064, 0.16, 0.40, or 1.0 micrograms/kg, po) or vehicle on Day 15 of gestation were evaluated at various stages of development; effects on spermatogenesis and male reproductive capability are reported herein. Testis, epididymis, and cauda epididymis weights were decreased in a dose-related fashion at 32, 49, 63, and 120 days of age, that is, when males were at the juvenile, pubertal, postpubertal, and mature stages of sexual development, respectively. When measured on Days 49, 63, and 120, daily sperm production by the testis was reduced at the highest maternal TCDD dose to 57-74% of the control rate. Cauda epididymal sperm reserves in 63- and 120-day-old males were decreased to as low as 25 and 44%, respectively, of control values, although the motility and morphology of these sperm appeared to be unaffected. The magnitude of the effects described above tended to lessen with time; nevertheless, the decreases in epididymis and cauda epididymis weights, daily sperm production, and cauda epididymal sperm number were statistically significant at the lowest maternal dose tested (0.064 micrograms TCDD/kg) on Day 120 and at most earlier times. To determine if in utero and lactational TCDD exposure also affects male reproductive capability, rats were mated at approximately 70 and 120 days of age with control females. Little if any effect on fertility was seen, and the survival and growth of offspring was unaffected. These results are not inconsistent with the pronounced reductions in daily sperm production and cauda epididymal sperm reserves caused by perinatal TCDD exposure since rats produce and ejaculate far more sperm than are required for normal fertility. The TCDD-induced reduction in spermatogenesis cannot be accounted for by concurrent effects on plasma follicle-stimulating hormone or androgen concentrations or by undernutrition. To investigate the nature of the spermatogenic lesion, leptotene spermatocyte to Sertoli cell ratios were determined.(ABSTRACT TRUNCATED AT 400 WORDS)

Primary ovarian insufficiency (POI), also known as premature ovarian failure, is a disorder of infertility characterized by amenorrhoea, low estrogen levels and increased gonadotropin levels in women aged <40 years. POI is the result of premature exhaustion of the follicle pool or can be attributed to follicular dysfunction, for example, owing to mutations in the follicle-stimulating hormone receptor or steroidogenic cell autoimmunity. Moreover, advances in cancer therapeutics over the past decades have led to increasing survival rates for both paediatric and adult malignancies. Given the gonadotoxic effect of many cancer treatments, more women develop POI. A marker that predicts whether women are at risk of POI would, therefore, aid in early diagnosis and fertility counselling. Anti-Müllerian hormone (AMH), a growth factor produced solely by small, growing follicles in the ovary, might constitute such a marker, as serum levels of this hormone correlate strongly with the number of growing follicles. In addition, AMH could potentially help assess the progression of ovarian senescence, as serum AMH levels are independent of hypothalamic-pituitary-gonadal axis function and decrease to undetectable levels at menopause. In cancer survivors, serum AMH levels correlate with the extent of gonadal damage. In this Review, we provide an overview of the current studies that have measured AMH in women with POI of various aetiologies and discuss its possible application as a marker to determine ovarian reserve.

OBJECTIVE

To assess the predictive performance of the antral follicle count (AFC) as a test for ovarian reserve in IVF patients and to compare this performance with that of basal FSH level.

METHODS

Meta-analysis.

METHODS

Tertiary fertility center.

METHODS

Patients undergoing IVF.

METHODS

None.

METHODS

Poor ovarian response, nonpregnancy.

RESULTS

We identified 11 studies on AFC and an updated total of 32 studies on basal FSH from the literature on the basis of preset criteria. The estimated summary receiver operating characteristic (ROC) curves showed AFC to perform well in the prediction of poor ovarian response. Also, prediction of poor ovarian response seemed to be more accurate with AFC compared with basal FSH. The estimated summary ROC curves for the prediction of nonpregnancy indicated a poor performance for both AFC and basal FSH.

CONCLUSIONS

Transvaginal ultrasonography is an easy-to-perform and noninvasive method that provides essential predictive information on ovarian responsiveness. The predictive performance of AFC toward poor response is significantly better than that of basal FSH. Therefore, AFC might be considered the test of first choice in the assessment of ovarian reserve prior to IVF.

Recombinant expression of truncated receptors for luteinizing hormone/chorionic gonadotropin (LH/CG) revealed that the amino-terminal leucine-rich repeats 1-8 of the extracellular receptor domain bind human chorionic gonadotropin (hCG) with an affinity (Kd = 0.72 +/- 0.2 nM) similar to that of the native LH/CG receptor (Kd = 0.48 +/- 0.05 nM). LH/CG receptor leucine-rich repeats 1-8 were used to replace homologous sequences in the closely related receptor for follicle stimulating hormone (FSH). Cells expressing such chimeric LH/CG-FSH receptors bind hCG and show elevated cylic AMP levels when stimulated by hCG but not by recombinant human FSH (rhFSH). Similarly, a chimeric LH/CG receptor in which leucine-rich repeats 1-11 originated from the FSH receptor is activated by rhFSH but not by hCG. For this chimera, no residual [125I] hCG binding was observed in a range of 2 pM to 10 nM. Our results demonstrate that specificity of gonadotropin receptors is determined by a high affinity hormone binding site formed by the amino-terminal leucine-rich receptor repeats.

Around 400 follicles sequentially mature and ovulate during an average woman's reproductive lifetime. From birth to the menopause, the other approximately 99.98% of her follicles begin development but never complete it. Instead they default to atresia due to inadequate stimulation by follicle stimulating hormone (FSH). Follicular growth to the stage of antrum formation (approximately 0.25 mm diameter) is independent of gonadotrophic stimulation. Antrum formation and further growth to the stage at which follicles become potentially able to begin preovulatory development (2-5 mm diameter) require tonic stimulation by FSH. Before onset of puberty, blood concentrations of FSH do not rise sufficiently to sustain development beyond this stage, therefore all antral follicles become atretic. After puberty, as each menstrual cycle begins, FSH concentrations rise beyond a critical 'threshold' and multiple follicles are recruited to begin pre-ovulatory development. Due to increases in its responsiveness to FSH and luteinizing hormone (LH), one of these follicles becomes selected to ovulate while the remainder become atretic. At mid-follicular phase, the dominant follicle reaches>> or = 10 mm in diameter and increasingly synthesizes oestradiol. Tonic stimulation by FSH and LH, underpinned by local paracrine signalling, maintains oestrogen secretion by the dominant follicle, which grows to>> or = 20 mm in diameter before it ovulates in response to the mid-cycle LH surge. The development-related response to LH shown by the pre-ovulatory follicle raises the possibility that exogenous LH might be used as an adjunct to therapy with exogenous FSH in clinical ovulation induction regimens where the aim is to induce monovulation.

Tooth eruption is a complex and tightly regulated process that involves cells of the tooth organ and the surrounding alveolus. Mononuclear cells (osteoclast precursors) must be recruited into the dental follicle prior to the onset of eruption. These cells, in turn, fuse to form osteoclasts that resorb alveolar bone, forming an eruption pathway for the tooth to exit its bony crypt. Some of the molecules possibly involved in the signaling cascades of eruption have been proposed in studies from null mice, osteopetrotic rodents, injections of putative eruption molecules, and cultured dental follicle cells. In particular, recruitment of the mononuclear cells to the follicle may require colony-stimulating factor-one (CSF-1) and/or monocyte chemotactic protein-1 (MCP-1). Osteoclastogenesis is needed for the bone resorption and may involve inhibition of osteoprotegerin transcription and synthesis in the follicle, as well as enhancement of receptor activator of NF kappa B ligand (RANKL), in the adjacent alveolar bone and/or in the follicle. Paracrine signaling by parathyroid-hormone-related protein and interleukin -1 alpha, produced in the stellate reticulum adjacent to the follicle, may also play a role in regulating eruption. Osteoblasts might also influence the process of eruption, the most important physiologic role likely being at the eruptive site, in the formation of osteoclasts through signaling via the RANKL/OPG pathway. Evidence thus far supports a role for an osteoblast-specific transcription factor, Cbfa1 (Runx2), in molecular events that regulate tooth eruption. Cbfa1 is also expressed at high levels by the dental follicle cells. This review concludes with a discussion of the several human conditions that result in a failure of or delay in tooth eruption.

Although androgen excess is considered detrimental to women's health and fertility, global and ovarian granulosa cell-specific androgen-receptor (AR) knockout mouse models have been used to show that androgen actions through ARs are actually necessary for normal ovarian function and female fertility. Here we describe two AR-mediated pathways in granulosa cells that regulate ovarian follicular development and therefore female fertility. First, we show that androgens attenuate follicular atresia through nuclear and extranuclear signaling pathways by enhancing expression of the microRNA (miR) miR-125b, which in turn suppresses proapoptotic protein expression. Second, we demonstrate that, independent of transcription, androgens enhance follicle-stimulating hormone (FSH) receptor expression, which then augments FSH-mediated follicle growth and development. Interestingly, we find that the scaffold molecule paxillin regulates both processes, making it a critical regulator of AR actions in the ovary. Finally, we report that low doses of exogenous androgens enhance gonadotropin-induced ovulation in mice, further demonstrating the critical role that androgens play in follicular development and fertility. These data may explain reported positive effects of androgens on ovulation rates in women with diminished ovarian reserve. Furthermore, this study demonstrates mechanisms that might contribute to the unregulated follicle growth seen in diseases of excess androgens such as polycystic ovary syndrome.

Assisted hatching by zona drilling using acidic Tyrode's solution was performed during three randomized trials in 330 in-vitro fertilization patients. The trials were designed in order to study the overall effect of the procedure and whether characteristic patient [i.e. maternal age and basal levels of follicle stimulating hormone (FSH)] and embryonic features (i.e. zona pellucida thickness) are important for the decision to perform assisted hatching routinely. Couples (n = 137; Trial 1) in whom the female partner had normal basal FSH levels were randomized in a control group (without micromanipulation) and a zona drilling group (all embryos micromanipulated). The incidence of implantation (67/239; 28%) of zona-drilled embryos compared favourably with that of control embryos (49/229; 21%), but the difference was not significant. Retrospective analysis revealed that those embryos whose zonae were thicker than 15 microns were rescued. In order to test the validity of this finding, selective assisted hatching was performed on embryos with a poor prognosis in 163 other patients (Trial 2). The couples were randomized into a control group and a group in which embryos were selectively zona-drilled, based on zona thickness and other embryonic features. The rate of embryonic implantation in the selectively zona-drilled group was 25% (70/278), significantly (P less than 0.05) higher than that of control embryos (51/285; 18%). Although it was demonstrated retrospectively and prospectively that assisted hatching by zona drilling is effective in embryos with thick zonae (greater than or equal to 15 microns), patients whose embryos have thin (less than 13 microns) zonae may be jeopardized by the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)