Visser, J.A.

Serum anti-Müllerian hormone and inhibin B concentrations are not useful predictors of ovarian response during ovulation induction treatment with recombinant follicle-stimulating hormone in women with polycystic ovary syndrome (Article)

2011-08-01T00:00:00Z

Objective: To describe changes of anti-Müllerian hormone (AMH) and inhibin B during low-dose gonadotropin ovulation induction (OI) treatment in women with polycystic ovary syndrome (PCOS), and thus disturbed selection of the dominant follicle. Design: Observational study. Setting: A referral fertility clinic. Patient(s): Women with PCOS (n = 48) and normo-ovulatory women (n = 23). Intervention(s) and Main Outcome Measure(s): Serum AMH, inhibin B, FSH, and E2concentrations were measured at start of stimulation, on the day of follicle selection, and at administration of hCG during OI cycles and were compared with concentration measured during the normal menstrual cycle. Result(s): Development of a single dominant follicle was observed in 92% of all OI cycles, reflected by similar E2concentrations compared with those in spontaneous cycles. AMH concentrations were constant during low-dose ovarian stimulation. Inhibin B concentrations remained elevated in patients with PCOS, suggesting prolonged survival of small antral follicles, whereas in controls inhibin B concentrations declined during the late follicular phase. Conclusion(s): The lack of change in AMH and inhibin B concentrations suggest that follicle dynamics during low-dose stimulation seem different from those during controlled ovarian hyperstimulation. In addition, constant AMH and inhibin B levels suggest that neither AMH nor inhibin B is an accurate marker of ovarian response after low-dose gonadotropin OI in patients with PCOS. Copyright

Acute effects of acylated and unacylated ghrelin on total and high molecular weight adiponectin in morbidly obese subjects (Article)

2011-06-01T00:00:00Z

Background: Energy homeostasis and body weight are regulated by a highly complex network involving the brain, the digestive tract, and white adipose tissue (WAT). Knowledge about signaling pathways connecting digestive tract and WAT is limited. Gut hormone ghrelin and adipokine adiponectin are both decreased in obesity and they share a potent effect on insulin sensitivity: both adiponectin and the combination of acylated (AG) and unacylated ghrelin (UAG) improve insulin sensitivity. Arm: In the present study, we evaluated whether acute administration of UAG alone or combined with AG affects adiponectin concentrations. Subjects and methods: Eight morbidly obese non-diabetic subjects were treated with either UAG 200 μg, UAG 100 μg + AG 100 μg (Comb), or placebo in 3 episodes in a double blind randomized cross-over design. Study medication was administered as single iv bolus injections at 09:00 h after an overnight fast. High molecular weight (HMW) and total adiponectin, glucose, insulin, and total ghrelin and AG were measured up to 1 h after administration. Results: HMW and total adiponectin concentrations did not change after administration of either UAG or Comb, nor were they different from placebo. Insulin concentrations decreased significantly after acute administration of Comb, reaching a minimum at 20 min: 58.2±3.9% of baseline. Conclusions: Acute iv administration of UAG and the combination of UAG and AG in morbidly obese non-diabetic subjects without overt diabetes does not affect total or HMW adiponectin concentrations, neither directly nor indirectly by changing insulin concentrations.

Fertility and ovarian function in high-dose estrogen-treated tall women (Article)

2011-04-01T00:00:00Z

Background/Objective: High-dose estrogen treatment to reduce final height of tall girls has been shown to interfere with fertility. Ovarian function has not been studied. We therefore evaluated fertility and ovarian function in tall women who did or did not receive such treatment in adolescence. Methods: This was a retrospective cohort study of 413 tall women aged 23-48 yr, of whom 239 women had been treated. A separate group of 126 fertile, normoovulatory volunteers aged 22-47 yr served as controls. Results: Fertility was assessed in 285 tall women (157 treated, 128 untreated) who had attempted to conceive. After adjustment for age, treated women were at increased risk of experiencing subfertility [odds ratio (OR) 2.29, 95% confidence interval (CI) 1.38-3.81] and receiving infertility treatments (OR 3.44,95%CI 1.76-6.73). Moreover, fecunditywasnotably affected because treated women had significantly reduced odds of achieving at least one live birth (OR 0.26, 95% CI 0.13-0.52). Remarkably, duration of treatment was correlated with time to pregnancy (r = 0.23, P = 0.008). Ovarian function was assessed in 174 tall women (119 treated, 55 untreated). Thirty-nine women (23%) exhibited a hypergonadotropic profile. After adjusting for age category, treated women had significantly higher odds of being diagnosed with imminent ovarian failure (OR 2.83, 95% CI 1.04-7.68). Serum FSH levels in these women were significantly increased, whereas antral follicle counts and serum anti-Müllerian hormone levels were decreased. Conclusion: High-dose estrogen-treated tall women are at risk of subfertility in later life. Their fecundity is significantly reduced. Treated women exhibit signs of accelerated ovarian aging with concomitant follicle pool depletion, which may be the basis of the observed subfertility. Copyright

Preconception folic acid use modulates estradiol and follicular responses to ovarian stimulation (Article)

2011-02-01T00:00:00Z

Background: Folate is a methyl donor. Availability of folate affects DNA methylation profiles and thereby gene expression profiles. We investigated the effects of low-dose folic acid use (0.4 mg/d) on the ovarian response to mild and conventional ovarian stimulation in women. Methods: In a randomized trial among subfertile women, 24 and 26 subjects received conventional and mild ovarian stimulation, respectively. Blood samples were taken during the early follicular phase of the cycle prior to treatment and on the day of human chorionic gonadotropin administration for determination of serum total homocysteine, anti-Müllerian hormone (AMH), estradiol, and folate. Folic acid use was validated by questionnaire and serum folate levels. Preovulatory follicles were visualized, counted, and diameters recorded using transvaginal ultrasound. The relation between folic acid use and ovarian response was assessed using linear regression analysis. Results: Folic acid use modified the ovarian response to ovarian stimulation treatment. The estradiol response was higher in nonfolic acid users receiving conventional treatment [βinteraction=0.52 (0.07- 0.97); P = 0.03], and this effect was independent of serum AMH levels and the preovulatory follicle count. In the conventional treatment, themeanfolliclenumberwasalso greater in nonusers compared with the users group (14.1 vs. 8.9, P = 0.03). Conclusion: Low-dose folic acid use attenuates follicular and endocrine responses to conventional stimulation, independent of AMH and follicle count. The nature of this observation suggests that the effect of folic acid is most prominent during early follicle development, affecting immature follicles. Deleterious effects of folate deficiency, like DNA hypomethylation and oxidative stress, can help to explain our observations.

Influence of preterm birth and small birth size on serum anti-Müllerian hormone levels in young adult women (Article)

2010-12-01T00:00:00Z

Background/objectives: Preterm birth has been associated with reduced reproduction rates, and controversies remain regarding the effect of being born small for gestational age (SGA) on ovarian function. Recent findings in young men showed no effect of preterm and SGA birth on testis function. We hypothesised that follicle pool size in young adult women is also not affected by preterm and SGA birth. Design/methods: In 279 young women of the PROGRAM/PREMS study, aged 18-24 years, the influence of gestational age, birth length and birth weight on serum levels of anti-Müllerian hormone (AMH) was analysed with multiple regression modelling. Additionally, AMH levels were analysed in preterm- versus term-born females and in three subgroups: females born SGA with either short stature or catch-up growth (SGA-CU), and females born term and appropriate for gestational age with normal stature (AGA controls). Results: Preterm and SGA birth did not affect AMH and other hormone levels. Older age at menarche and oral contraceptive pill use (OC-use) were related to lower AMH levels, and maternal smoking during gestation was related to higher AMH levels. After correction for maternal smoking, lower socioeconomic status (SES) was associated with lower AMH levels. In subgroup comparisons, SGA-CU women showed higher AMH levels than AGA controls, also after adjustment for several factors. Conclusion: Preterm and SGA birth did not affect AMH levels. Factors associated with serum AMH levels were OC-use, age at menarche, maternal smoking during gestation and SES. We conclude that preterm- and/or SGA-born females are not likely to have a reduced follicle pool size.

Thirty new loci for age at menarche identified by a meta-analysis of genome-wide association studies (Article)

2010-12-01T00:00:00Z

To identify loci for age at menarche, we performed a meta-analysis of 32 genome-wide association studies in 87,802 women of European descent, with replication in up to 14,731 women. In addition to the known loci at LIN28B (P = 5.4 × 10 -60) and 9q31.2 (P = 2.2 × 10 -33), we identified 30 new menarche loci (all P < 5 × 10 -8) and found suggestive evidence for a further 10 loci (P < 1.9 × 10 -6). The new loci included four previously associated with body mass index (in or near FTO, SEC16B, TRA2B and TMEM18), three in or near other genes implicated in energy homeostasis (BSX, CRTC1 and MCHR2) and three in or near genes implicated in hormonal regulation (INHBA, PCSK2 and RXRG). Ingenuity and gene-set enrichment pathway analyses identified coenzyme A and fatty acid biosynthesis as biological processes related to menarche timing.

Meta-analysis of genome-wide association data identifies two loci influencing age at menarche (Article)

2009-06-01T00:00:00Z

We conducted a meta-analysis of genome-wide association data to detect genes influencing age at menarche in 17,510 women. The strongest signal was at 9q31.2 (P = 1.7 × 10 9), where the nearest genes include TMEM38B, FKTN, FSD1L, TAL2 and ZNF462. The next best signal was near the LIN28B gene (rs7759938; P = 7.0 × 10 9), which also influences adult height. We provide the first evidence for common genetic variants influencing female sexual maturation.

Loci at chromosomes 13, 19 and 20 influence age at natural menopause (Article)

2009-06-01T00:00:00Z

We conducted a genome-wide association study for age at natural menopause in 2,979 European women and identified six SNPs in three loci associated with age at natural menopause: chromosome 19q13.4 (rs1172822; -0.4 year per T allele (39%); P = 6.3 × 10 11), chromosome 20p12.3 (rs236114; +0.5 year per A allele (21%); P = 9.7 × 10 11) and chromosome 13q34 (rs7333181; +0.5 year per A allele (12%); P = 2.5 × 10 8). These common genetic variants regulate timing of ovarian aging, an important risk factor for breast cancer, osteoporosis and cardiovascular disease.

Anti-Müllerian hormone in men with normal and reduced sperm concentration and men with maldescended testes (Article)

2009-05-01T00:00:00Z

Objective: To evaluate serum anti-Müllerian hormone (AMH) in well-characterized men with normal and reduced sperm concentration and in men with a history of or persistent maldescended testes as a possible clinical marker of male factor infertility and/or maldescended testes. Design: Retrospective analysis of 199 men selected from our database (Androbase). Setting: The university-based Institute of Reproductive Medicine. Patient(s): One hundred eight men with normal and 60 men with reduced sperm concentration without known cause of infertility and additionally 31 infertile men with current or former maldescended testes were evaluated. Intervention(s): Serum AMH was analyzed by an in-house ELISA. Main Outcome Measure(s): Hormone and semen parameters were compared and correlated with AMH. Result(s): No significant differences were found in AMH levels. Only in men with maldescended testes did AMH correlate negatively with FSH and positively with testicular volume and sperm concentration. No correlations between AMH and LH or testosterone (T) were found. Conclusion(s): Anti-Müllerian hormone serum levels are not significantly affected by impaired spermatogenesis in general but are correlated with spermatogenic parameters in men with current or former maldescended testes. Therefore, AMH measurement does not improve clinical routine diagnostics but should be evaluated further in patients with maldescended testes. Anti-Müllerian hormone might serve as a marker of Sertoli cell number, function, and/or maturation in these men.

Assessment of ovarian reserve in adult childhood cancer survivors using anti-Müllerian hormone (Article)

2009-04-01T00:00:00Z

BACKGROUND: The aim was to assess possible treatment-induced gonadal damage in a cohort of adult female childhood cancer survivors (CCS) using anti-Müllerian hormone (AMH), the most sensitive marker of ovarian reserve. METHODS: A total cohort of 185 survivors was compared with 42 control subjects. The median follow-up time was 18.1 years (range 4.1-43.2 year). RESULTS: Median AMH concentrations in the analysed cohort were not different from controls (median 1.7 versus 2.1 g/l; P = 0.57). However, AMH levels were lower than the 10th percentile of normal values in 27 (49/182) of our survivors. In addition, 43 (79/182) had AMH levels lower than 1.4 g/l, a previously established cut-off value which predicts ongoing pregnancy after assisted reproduction. There were no differences in AMH levels in subgroups classified according to disease. However, survivors treated with three or more procarbazine containing chemotherapy cycles had significantly lower AMH levels than controls (median 0.5 g/l; P = 0.004). Also survivors treated with abdominal or total body irradiation had significantly lower AMH levels than controls (median < 0.1 g/l; P < 0.001). CONCLUSIONS: AMH can be used to identify subgroups of CCS at risk for decreased fertility or premature ovarian failure. In these survivors, options for fertility preservation should be considered prior to starting treatment since they may be at risk for poor chances of pregnancy after assisted reproductive treatment.

Variants in the ACVR1 gene are associated with AMH levels in women with polycystic ovary syndrome (Article)

2009-01-01T00:00:00Z

BACKGROUND: Polycystic ovaries display an increased number of pre-antral and antral follicles compared with normal ovaries, suggesting that early and late follicle development are disturbed. The pathophysiology of this process is poorly understood. Since the transforming growth factor β family members, anti-Müllerian hormone (AMH) and bone morphogenetic proteins (BMPs), inhibit FSH sensitivity, their signalling may contribute to the aberrant follicle development in these women. Here, we investigated the role of ALK2, a type I receptor for AMH/BMP signalling, in PCOS using a genetic approach. METHODS: Seven single nucleotide polymorphisms in the ACVR1 gene, encoding ALK2, were genotyped in 359 PCOS patients and 30 normo-ovulatory and 3543 population-based control women, and haplotypes were determined. Subsequently, the association of ACVR1 variants with ovarian parameters and hormone levels was investigated. RESULTS: The polymorphisms rs1220134, rs10497189 and rs2033962 and their corresponding haplotypes did not show different frequencies from controls, but were associated with AMH levels in PCOS women (P = 0.001, P = 0.002 and P = 0.007, respectively). Adjustment for follicle number revealed that the association with AMH levels was, in part, independent from follicle number, suggesting that variants in ACVR1 also influence AMH production per follicle. CONCLUSIONS: Genetic variation within ACVR1 is associated with AMH levels and follicle number in PCOS women, suggesting that ALK2 signalling contributes to the disturbed folliculogenesis in PCOS patients.

Anti-Müllerian hormone and ovarian dysfunction (Article)

2008-11-01T00:00:00Z

Anti-Müllerian hormone (AMH) has important roles in postnatal ovarian function. Produced by ovarian granulosa cells, AMH is involved in initial follicle development. In fact, serum AMH level correlates with ovarian follicle number. In patients with polycystic ovary syndrome (PCOS), AMH levels are elevated, which indicates its potential relevance in PCOS diagnosis and management. AMH represents a useful clinical marker for the assessment of ovarian reserve in cases of subfertility caused by advanced age in women. A potential role for AMH in dominant follicle selection has also been suggested. Future challenges comprise the availability of a well-standardized assay and the development of AMH agonists and antagonists as possible tools to manipulate ovarian function for contraception or ovarian longevity.

Correlation of serum anti-Müllerian hormone with accelerated follicle loss following 4-vinylcyclohexene diepoxide-induced follicle loss in mice (Article)

2008-10-01T00:00:00Z

A chemically induced model of ovarian failure has been developed in rodents, and was used to test whether or not anti-Müllerian hormone (AMH) can be used as a non-invasive measure of primordial follicle numbers. Repeated exposures of mice to 4-vinylcyclohexene diepoxide (VCD) induce loss of primordial and earliest growing ovarian follicles. An accelerated exposure regimen was used to eliminate small ovarian follicles in C57BL6/J mice (240 mg VCD/kg/day, 5 days, i.p.). Follicle populations were determined and correlated with circulating AMH levels. Exposures decreased only primordial and small primary follicles by 96% on day 16 after initiating exposures, followed by almost complete follicle elimination on days 37-100. AMH levels in VCD-exposed mice were similar to vehicle-treated mice on day 16, but became significantly lower or undetectable at later time points. Thus, AMH correlated well with growing follicle numbers. AMH only correlated with primordial follicles at time points after ovarian insult at which their loss led to decreased growing follicle numbers.

A functional anti-müllerian hormone gene polymorphism is associated with follicle number and androgen levels in polycystic ovary syndrome patients (Article)

2008-04-01T00:00:00Z

Context: The common characteristic of polycystic ovary syndrome (PCOS) is a disturbance in the selection of the dominant follicle, resulting in anovulation. In PCOS women, serum anti-Müllerian hormone (AMH) levels are elevated. Because AMH decreases FSH sensitivity in mice, the elevated AMH levels may contribute to the disturbed follicle selection in PCOS women. Objective: The objective of the study was to investigate the role of the AMH signaling pathway in the pathophysiology of PCOS using a genetic approach. Design: The association of the AMH Ile49Ser (rs10407022) and the AMH type II receptor -482 A>G (rs2002555) polymorphism with PCOS susceptibility and phenotype was studied in a large cohort of PCOS women. Setting/Subjects: A total of 331 women with PCOS, 32 normoovulatory controls, and 3635 population-based controls were included. Main Outcome Measures: Ovarian parameters, serum AMH, FSH, androgen, and estradiol levels were measured. Results: Genotype and allele frequencies for the AMH Ile49Ser and AMH type II receptor -482 A>G polymorphism were similar in PCOS women and controls. However, within the group of PCOS women, carriers of the AMH49Ser allele less often had polycystic ovaries (92.7 vs. 99.5%, P = 0.0004), lower follicle numbers (P = 0.03), and lower androgen levels, compared with noncarriers (P = 0.04). In addition, in vitro studies demonstrated that the bioactivity of the AMH49Ser protein is diminished, compared with the AMH49Ile protein (P < 0.0001). Conclusions: Genetic variants in the AMH and AMH type II receptor gene do not influence PCOS susceptibility. However, our results suggest that the AMH Ile49Ser polymorphism contributes to the severity of the PCOS phenotype. Copyright

Rising follicle-stimulating hormone levels with age accelerate female reproductive failure (Article)

2007-09-01T00:00:00Z

Rising serum FSH levels is one of the earliest signs of human female reproductive aging. Whether or not elevated FSH remains a passive reflection of a diminishing ovarian follicle pool or actively contributes to declining female fertility with age has not been established. We therefore investigated female reproduction in mice expressing progressively rising serum levels of transgenic human FSH (Tg-FSH, 2.5-10 IU/liter) independently of follicle depletion. We show that serum LH and estradiol levels and uterine size remained normal in Tg-FSH females, whereas ovarian weight and corpora lutea number were significantly increased up to 1.3- and 5-fold, respectively. Furthermore, the monotrophic FSH rise produced a striking biphasic effect on female fertility. Tg-FSH females less than 22 wk old delivered increased litter sizes, then beyond 23 wk, litter sizes decreased rapidly culminating in premature infertility despite continued ovary follicle development, and increased ovulation and uterine embryo implantation sites as well as normal serum levels of anti-Mullerian hormone, a marker of ovarian follicle reserve. We found that rising circulating Tg-FSH produced premature infertility by increasing embryo-fetal resorption and parturition failure with age. Thus, our Tg-FSH mice present a novel paradigm to investigate selective contributions of elevated FSH to age-related female infertility, which revealed that rising FSH levels, despite no exhaustion of ovarian reserve, actively accelerates female reproductive aging primarily by postimplantation reduction of embryo-fetal survival. Copyright

A polymorphism in the AMH type II receptor gene is associated with age at menopause in interaction with parity (Article)

2007-09-01T00:00:00Z

Background: Anti-Müllerian hormone (AMH) inhibits primordial follicle recruitment in the mouse ovary. We hypothesize that in women AMH signaling also regulates the usage of the primordial follicle pool and hence influences the onset of menopause. Since age at menopause has a strong genetic component, we investigated the role of AMH signaling using a candidate gene approach. Methods: In two large population-based cohorts of Dutch post-menopausal women (n = 2381 and n = 248), we examined the association between two polymorphisms, one in the AMH gene and one in the AMH type II receptor (AMHR2) gene, and natural age at menopause. Results: The AMH Ile49Ser polymorphism (rs10407022) was not associated with age at menopause in either cohort. In the Rotterdam cohort, the AMHR2 -482 A > G polymorphism (rs2002555) was associated with age at menopause in interaction with the number of offspring (P = 0.001). Nulliparous women homozygous for the G-allele entered menopause 2.6 years earlier compared with nulliparous women homozygous for the A-allele (P = 0.005). In the LASA cohort, women with the G/G genotype tended to enter menopause 2.8 years earlier compared with the A/A genotype (P = 0.063). Conclusions: The observed association of the AMHR2 -482 A > G polymorphism with natural age at menopause suggests a role for AMH signaling in the usage of the primordial follicle pool in women.

The activin A-follistatin system: Potent regulator of human extracellular matrix mineralization (Article)

2007-09-01T00:00:00Z

Bone quality is an important determinant of osteoporosis, and proper osteoblast differentiation plays an important role in the control and maintenance of bone quality. We investigated the impact of activin signaling on human osteoblast differentiation, extracellular matrix formation, and mineralization. Activins belong to the transforming growth factor-β superfamily and activin A treatment strongly inhibited mineralization in osteoblast cultures, whereas the activin antagonist follistatin increased mineralization. Osteoblasts produced activin A and follistatin in a differentiation-dependent manner, leading to autocrine regulation of extracellular matrix formation and mineralization. In addition, mineralization in a vascular smooth muscle cell-based model for pathological calcification was inhibited. Comparative activin A and follistatin gene expression profiling showed that activin signaling changes the expression of a specific range of extracellular matrix proteins prior to the onset of mineralization, leading to a matrix composition with reduced or no mineralizing capacity. These findings demonstrate the regulation of osteoblast differentiation and matrix mineralization by the activin A-follistatin system, providing the possibility to control bone quality as well as pathological calcifications such as atherosclerosis by using activin A, follistatin, or analogs thereof.

Anti-Müllerian hormone and anti-Müllerian hormone type II receptor polymorphisms are associated with follicular phase estradiol levels in normo-ovulatory women (Article)

2007-06-01T00:00:00Z

Background: In mice, anti-Müllerian hormone (AMH) inhibits primordial follicle recruitment and decreases FSH sensitivity. Little is known about the role of AMH in human ovarian physiology. We hypothesize that in women AMH has a similar role in ovarian function as in mice and investigated this using a genetic approach. Methods: The association ofthe AMH Ile49Ser and the AMH type II receptor (AMHR2) -482 A > G polymorphisms with menstrual cycle characteristics was studied in a Dutch (n = 32) and a German (n = 21) cohort of normo-ovulatory women. Results: Carriers of the AMH Ser49allele had higher serum estradiol (E2) levels on menstrual cycle day 3 when compared with non-carriers in the Dutch cohort (P = 0.012) and in the combined Dutch and German cohort (P = 0.03). Carriers of the AMHR2 -482G allele also had higher follicular phase E2levels when compared with non-carriers in the Dutch cohort (P = 0.028), the German cohort (P = 0.048) and hence also the combined cohort (P = 0.012). Women carrying both AMH Ser49and AMHR2 -482G alleles had highest E2levels (P = 0.001). For both polymorphisms no association with serum AMH or FSH levels was observed. Conclusions: Polymorphisms in the AMH and AMHR2 genes are associated with follicular phase E2levels, suggesting a role for AMH in the regulation of FSH sensitivity in the human ovary.

Increased oocyte degeneration and follicular atresia during the estrous cycle in anti-Müllerian hormone null mice (Article)

2007-05-01T00:00:00Z

Anti-Müllerian hormone (AMH) plays an important role in folliculogenesis. AMH null mice display an increased recruitment of primordial follicles. Nevertheless, these mice do not have proportionally more preovulatory follicles. Therefore, AMH null mice provide an interesting genetic model to study the regulation of species-specific number of preovulatory follicles. We studied the follicle pool throughout the estrous cycle at 4 months of age. Analysis of the follicle pool revealed that AMH null mice have an increased and earlier cyclic recruitment of growing follicles despite a blunted FSH surge at estrus. However, FSH levels at estrus were apparently too low to support growth to the preovulatory stage because an increased level of atresia was observed, which neutralized the increased cyclic recruitment. When AMH null mice were subjected to a superovulation scheme, the rise in FSH levels resulted in the rescue of the recruited cohort of growing follicles. Analysis of the follicle pool also revealed that the increased recruitment of primordial follicles in AMH null mice was neutralized by an increased loss of follicles during the transition from small preantral to large preantral follicle. This major loss of follicles was not completely reflected by a corresponding augmentation of atresia but did correspond with an increased number of oocyte remnants observed in AMH null mice. We conclude that a combination of increased oocyte degeneration and increased follicular atresia neutralizes the increased initial and cyclic recruitment in AMH null mice to a normal number of preovulatory follicles. Copyright