A study of 1,478 consecutive in vitro fertilization (IVF) cycles was made to determine if basal follicle-stimulating hormone (FSH) levels and age were independent predictors of IVF performance. Regression analyses indicated independent contributions of both basal FSH and age in predicting cancellation rate, peak estradiol, number of oocytes retrieved, fertilized, and transferred, and total and ongoing pregnancy rates. Miscarriage rate was unrelated to both age and basal FSH. Follicle-stimulating hormone level was a better predictor than age for all outcome variables examined and remained a significant predictor after accounting for age, etiology of infertility, and semen quality. The combined use of age and basal FSH in counseling patients improves the accuracy of prognosis, and may provide an index of functional ovarian reserve ("ovarian age").

Spermatogenesis in adult mammals is highly organized, with the goal being continual sperm production. Vertebrate testes are arranged into recurring cellular associations that vary with time and distance along the tubule. These changes over time and distance are designated the cycle of the seminiferous epithelium and the spermatogenic wave, respectively. In this Review, we briefly outline the roles that follicle-stimulating hormone (FSH) and testosterone play in regulating spermatogenesis and describe our current understanding of how vitamin A regulates germ cell differentiation and how it may lead to the generation of both the cycle of the seminiferous epithelium and the spermatogenic wave.

We sought to elucidate the role of AKT in follicle-stimulating hormone (FSH)-mediated granulosa cell (GC) differentiation. Our results define a signaling pathway in GCs whereby the inactivating phosphorylation of tuberin downstream of phosphatidylinositol (PI) 3-kinase/AKT activity leads to Rheb (Ras homolog enriched in brain) and subsequent mTOR (mammalian target of rapamycin) activation. mTOR then stimulates translation by phosphorylating p70 S6 kinase and, consequently, the 40 S ribosomal protein S6. Activation of this pathway is required for FSH-mediated induction of several follicular differentiation markers, including luteinizing-hormone receptor (LHR), inhibin-alpha, microtubule-associated protein 2D, and the PKA type IIbeta regulatory subunit. FSH also promotes activation of the transcription factor hypoxia-inducible factor-1 (HIF-1). FSH-stimulated HIF-1 activity is inhibited by the PI 3-kinase inhibitor LY294002, the Rheb inhibitor FTI-277 (farnesyltransferase inhibitor-277), and the mTOR inhibitor rapamycin. Finally, we find that the FSH-mediated up-regulation of reporter activities for LHR, inhibin-alpha, and vascular endothelial growth factor is dependent upon HIF-1 activity, because a dominant negative form of HIF-1alpha interferes with the up-regulation of these genes. These results show that FSH enhances HIF-1 activity downstream of the PI 3-kinase/AKT/Rheb/mTOR pathway in GCs and that HIF-1 activity is necessary for FSH to induce multiple follicular differentiation markers.

OBJECTIVE

To test the hypothesis that prevalence of women with menopausal symptoms of hot flushes; aches, joint pain, and stiffness; depressed mood; poor sleep; decreased libido; or vaginal dryness increases with progression through the menopausal transition.

METHODS

Women in the Penn Ovarian Aging Study were assessed longitudinally for 9 years. Data were obtained from structured interviews, a validated symptom questionnaire, menstrual bleeding dates and early follicular hormone measures (estradiol [E2], follicle-stimulating hormone [FSH], and inhibin b). Menopausal stages were based on menstrual bleeding patterns. Other risk factors included age, race, history of depression, current smoking, body mass index, and perceived stress. Generalized linear regression models for repeated measures were used to estimate associations among the variables with each symptom.

RESULTS

The prevalence of hot flushes; aches, joint pain, and stiffness; and depressed mood increased in the menopausal transition. Menopausal stage was associated with hot flushes (P<.001); aches joint pain, and stiffness (P<.001); and depressed mood (P=.002). Within-woman fluctuations of E2 were associated with hot flushes and aches. Poor sleep, decreased libido, and vaginal dryness were not associated with menopausal stages. There was 80% power to detect an absolute difference of 11% for libido and vaginal dryness and 17% for poor sleep in the prevalence of these symptoms in the late menopausal transition compared with premenopausal status.

CONCLUSIONS

The study highlights the role of menopausal stages for some symptoms of midlife women and indicates that stages in the transition to menopause are associated with hot flushes; aches, joint pain, and stiffness; and depressed mood. Fluctuations of E2, decreased levels of inhibin b, and increased FSH levels were associated with these symptoms.

METHODS

II.

Oocyte and embryo metabolism are closely linked with their subsequent developmental capacity. Lipids are a potent source of cellular energy, yet little is known about lipid metabolism during oocyte maturation and early embryo development. Generation of ATP from lipids occurs within mitochondria via beta-oxidation of fatty acids, with the rate-limiting step catalyzed by carnitine palmitoyl transferase I (CPT1B), a process also requiring carnitine. We sought to investigate the regulation and role of beta-oxidation during oocyte maturation and preimplantation development. Expression of Cpt1b mRNA, assessed by real-time RT-PCR in murine cumulus-oocyte complexes (COCs), increased following hormonal induction of oocyte maturation and ovulation in vivo with human chorionic gonadotropin (5 IU) and in embryos reaching the blastocyst stage. Beta-oxidation, measured by the production of (3)H(2)O from [(3)H]palmitic acid, was significantly increased over that in immature COCs following induction of maturation in vitro with epidermal growth factor (3 ng/ml) and follicle-stimulating hormone (50 mIU/ml). The importance of lipid metabolism for oocyte developmental competence and early embryo development was demonstrated by assessing the rate of embryo development following inhibition or upregulation of beta-oxidation with etomoxir (an inhibitor of CPT1B) or L-carnitine, respectively. Inhibition of beta-oxidation during oocyte maturation or zygote cleavage impaired subsequent blastocyst development. In contrast, L-carnitine supplementation during oocyte maturation significantly increased beta-oxidation, improved developmental competence, and in the absence of a carbohydrate energy supply, significantly increased 2-cell cleavage. Thus, carnitine is an important cofactor for developing oocytes, and fatty acids are an important energy source for oocyte and embryo development.

Bisphenol A (BPA) is a synthetic chemical used in the manufacture of materials present in many common consumer products. In experimental animals, BPA caused oocyte aneuploidy and reduced production of oestradiol. In a prospective cohort study, we investigated the association between urinary BPA concentrations and ovarian response among women undergoing in vitro fertilization (IVF) at the Massachusetts General Hospital (MGH) Fertility Center. The geometric mean of two specific-gravity (SG) adjusted urinary BPA concentrations collected during each IVF cycle was used as the cycle-specific BPA exposure level. BPA concentrations were measured using online solid phase extraction coupled to isotope dilution-high-performance liquid chromatography-tandem mass spectrometry. Peak serum oestradiol was measured using the Elecsys Estradiol II immunoassay kit. Multivariable mixed effect models and Poisson regression models adjusting for correlation between multiple IVF cycles in the same woman were used to evaluate the association between urinary BPA concentrations and ovarian response, adjusting for age, BMI and day 3 follicle stimulating hormone (FSH) levels, a clinical measure of ovarian reserve. Urinary BPA concentrations were measured in 84 women (mean age 35.6 years) undergoing 112 IVF cycles; 23 women (27%) contributed more than one IVF cycle. BPA concentrations ranged from <0.4 to 25.5 microg/L (geometric mean 2.52 +/- SD 3.2); 15% of urine samples had concentrations <0.4 microg/L. Peak serum oestradiol levels correlated with the total number of oocytes retrieved per cycle (r = 0.65, p < 0.001). For each log unit increase in SG-BPA, there was an average decrease of 12% (95% CI: 4, 23%; p = 0.007) in the number of oocytes retrieved and an average decrease of 213 pg/ml (95% CI: -407, -20; p = 0.03) in peak oestradiol. BPA was detected in the urine of the majority of women undergoing IVF, and was inversely associated with number of oocytes retrieved and peak oestradiol levels.

OBJECTIVE

To determine whether patterns of change in serum estradiol (E2) and FSH across the menopausal transition were associated with age at the final menstrual period (FMP).

METHODS

The Study of Women's Health Across the Nation (SWAN) is a seven-site, multiethnic, longitudinal study of the menopausal transition being conducted in 3302 menstruating women who were aged 42-52 yr at the 1996 study baseline.

METHODS

Annually collected serum was assayed for E2 and FSH levels. Patterns of hormone change were evaluated in the 1215 women with a documented natural FMP by follow-up visit 9 (2006) using semiparametric stochastic and piecewise linear mixed modeling.

RESULTS

The FSH pattern across the menopausal transition began with an increase 6.10 yr before the FMP, an acceleration 2.05 yr before the FMP, deceleration beginning 0.20 yr before the FMP, and attainment of stable levels 2.00 yr after the FMP, independent of age at the FMP, race/ethnicity, or smoking status. Obesity attenuated the FSH rise and delayed the initial increase to 5.45 yr before the FMP. The mean E2 concentration did not change until 2.03 yr before the FMP when it began decreasing, achieving maximal rate of change at the FMP, then decelerating to achieve stability 2.17 yr after the FMP. Obesity, smoking behavior, and being Chinese or Japanese were associated with some variation in E2 levels but not the pattern of E2 change.

CONCLUSIONS

Time spans and overall patterns of change in serum FSH and E2 across the menopausal transition were not related to age at FMP or smoking, whereas time spans but not overall patterns were related to obesity and race/ethnicity.

BACKGROUND

Obesity is considered a protective factor for osteoporosis improving bone mass and maintaining higher levels of estrogen during menopause.

OBJECTIVE

To determine the association of obesity with bone mineral density (BMD), and its relationship with sex hormone levels.

METHODS

A case-control study in Caucasian obese and non obese postmenopausal women.

METHODS

113 obese and 50 non-obese postmenopausal women.

METHODS

BMD (dual-photon X-ray absorptiometry) at cervical femur. Ward's triangle, proximal radius and lumbar spine. Plasma levels of glucose, insulin, total estrogen, follicle stimulating hormone (FSH), sex hormone binding globulin (SHBG), dehydroepiandrosterone sulfate (DHA-S) and testosterone.

RESULTS

Mean BMD at femoral sites were significantly higher in obese women (femoral neck: 0.849 +/- 0.124 g/cm2 vs 0.753 +/- 0.095 g/cm2, P < 0.001; Ward's triangle: 0.634 +/- 0.134 g/cm2 vs. 0.553 +/- 0.100 g/cm2, P < 0.001). Mean BMD at lumbar spine was 0.906 +/- 0.138 g/cm2 in obese women and 0.849 +/- 0.137 g/cm2 in non obese, P < 0.017. A decreased risk of osteopenia in femoral neck (Age adjusted OR = 0.36, 95%CI 0.17-0.75) and in lumbar spine (Age adjusted OR = 0.43, 95%CI 0.20-0.91) in obese women was observed. Although total estrogen were similar in both groups, in obese women, SHBG was lower (68.6 +/- 26.84 nmol/l vs. 85.1 +/- 31.18 nmol/l, P < 0.001), and postglucose load insulin levels were higher, than in non obese (77.2 +/- 50.4 Ul/ml vs. 49.4 +/- 24.1 Ul/ml, P < 0.0005).

CONCLUSIONS

The findings confirm a higher BMD in obese women and suggest that obesity exerts protection due to a decreased SHBG thus increasing free sex steroids. Besides, hyperinsulinemia may produce a decline in the production of IGFBG-1, leading to an increase of IGF-1, that may stimulate the proliferation of osteoblasts.

BACKGROUND

The contribution of reproductive hormones to mood has been the focus of considerable research. Results from clinical and epidemiological studies have been inconsistent. It remains unclear whether alterations in serum hormone levels across the menopausal transition are linked to depressive symptoms.

OBJECTIVE

To evaluate the relationship between serum hormone levels and high depressive symptoms and whether hormone levels or their change might explain the association of menopausal status with depressive symptoms previously reported in a national sample of midlife women.

METHODS

A longitudinal, community-based, multisite study of menopause. Data were collected at baseline and annually from December 1995 to January 2008 on a range of factors. Early follicular phase serum samples were assayed for levels of estradiol, follicle-stimulating hormone, testosterone, and dehydroepiandrosterone sulfate.

METHODS

Seven communities nationwide.

METHODS

A community-based sample of 3302 multiethnic women, aged 42 to 52 years, still menstruating and not using exogenous reproductive hormones. Main Outcome Measure Depressive symptoms assessed with the Center for Epidemiological Studies Depression Scale (CES-D). The primary outcome was a CES-D score of 16 or higher.

RESULTS

In multivariable random-effects logistic regression models, log-transformed testosterone level was significantly positively associated with higher odds of a CES-D score of 16 or higher (odds ratio = 1.15; 95% confidence interval, 1.01-1.31) across 8 years, and a larger increase in log-transformed testosterone from baseline to each annual visit was significantly associated with increased odds of a CES-D score of 16 or higher (odds ratio = 1.23; 95% confidence interval, 1.04-1.45). Less education, being Hispanic, and vasomotor symptoms, stressful life events, and low social support at each visit were each independently associated with a CES-D score of 16 or higher. No other hormones were associated with a CES-D score of 16 or higher. Being perimenopausal or postmenopausal compared with being premenopausal remained significantly associated with a CES-D score of 16 or higher in all analyses.

CONCLUSIONS

Higher testosterone levels may contribute to higher depressive symptoms during the menopausal transition. This association is independent of menopausal status, which remains an independent predictor of higher depressive symptoms.

Testosterone and follicle-stimulating hormone (FSH) are required to obtain full reproductive potential. In the testis, somatic Sertoli cells transduce signals from testosterone and FSH into the production of factors that are required by germ cells as they mature into spermatozoa. Recent advances in identifying new signaling pathways that are regulated by FSH and testosterone have allowed for refinement in the understanding of the independent, overlapping and synergistic actions of these hormones. In this review, we discuss the signaling pathways that are regulated by FSH and testosterone as well as the resulting metabolic and gene expression changes that occur as related to Sertoli cell proliferation, differentiation and the support of spermatogenesis.

OBJECTIVE

To analyze interactions between the thyroid-stimulating hormone receptor (TSHR) and a thyroid-stimulating human monoclonal autoantibody (M22) at the molecular level.

METHODS

A complex of part of the TSHR extracellular domain (amino acids 1-260; TSHR260) bound to M22 Fab was prepared and purified. Crystals suitable for X-ray diffraction analysis were obtained and the structure solved at 2.55 A resolution.

RESULTS

TSHR260 comprises of a curved helical tube and M22 Fab clasps its concave surface at 90 degrees to the tube length axis. The interface buried in the complex is large (2,500 A(2)) and an extensive network of ionic, polar, and hydrophobic bonding is involved in the interaction. There is virtually no movement in the atoms of M22 residues on the binding interface compared to unbound M22 consistent with "lock and key" binding. Mutation of residues showing strong interactions in the structure influenced M22 activity, indicating that the binding detail observed in the complex reflects interactions of M22 with intact, functionally active TSHR. The receptor-binding arrangements of the autoantibody are very similar to those reported for follicle-stimulating hormone (FSH) binding to the FSH receptor (amino acids 1-268) and consequently to those of TSH itself.

CONCLUSIONS

It is remarkable that the thyroid-stimulating autoantibody shows almost identical receptor-binding features to TSH although the structures and origins of these two ligands are very different. Furthermore, our structure of the TSHR and its complex with M22 provide foundations for developing new strategies to understand and control both glycoprotein hormone receptor activation and the autoimmune response to the TSHR.

The menopause is the permanent cessation of menstruation resulting from the loss of ovarian follicular activity. It is heralded by the menopausal transition, a period when the endocrine, biological, and clinical features of approaching menopause begin. A common initial marker is the onset of menstrual irregularity. The biology underlying the transition to menopause includes central neuroendocrine changes as well as changes within the ovary, the most striking of which is a profound decline in follicle numbers. Follicle-stimulating hormone (FSH) is an established indirect marker of follicular activity. In studies of groups of women, its concentration, particularly in the early follicular phase of the menstrual cycle, begins to increase some years before there are any clinical indications of approaching menopause. The rise in FSH is the result of declining levels of inhibin B (INH-B), a dimeric protein that reflects the fall in ovarian follicle numbers, with or without any change in the ability of the lining granulosa cells to secrete INH-B. Estradiol levels remain relatively unchanged or tend to rise with age until the onset of the transition and are usually well preserved until the late perimenopause, presumably in response to the elevated FSH levels. During the transition, hormone levels frequently vary markedly - hence, measures of FSH and estradiol are unreliable guides to menopausal status. Concentrations of testosterone have been reported to fall by about 50% during reproductive life, between the ages of 20 and 40. They change little during the transition and, after menopause, may even rise. Dehydroepiandrosterone (DHEA) and DHEAS, its sulphate, on the other hand, decline with age, without any specific influence of the menopause. Symptoms of the menopause can be interpreted as resulting primarily from the profound fall in estradiol, occurring over a 3- to 4-year period around final menses, a fall that presumably contributes importantly to the beginning, in the late perimenopause, of loss of bone mineral density.

The activins are pleiotropic members of the TGFbeta superfamily. Within the anterior pituitary gland, activins stimulate FSH synthesis in an autocrine/paracrine fashion by stimulating transcription of the FSHbeta subunit gene. Here, the mechanisms mediating this effect were investigated in the murine gonadotrope cell line, LbetaT2. Recombinant activin A and activin B dose- and time-dependently stimulated endogenous FSHbeta mRNA expression. FSHbeta primary transcript and mRNA levels were increased within 30-60 min, but these effects were blocked by preincubation with the transcription inhibitor actinomycin-D, suggesting that the FSHbeta gene is a direct target of the activin signal transduction cascade. In other systems, activin signals are transduced through a heteromeric serine/threonine receptor complex, which includes the signaling activin type IB receptor [activin receptor-like kinase 4 (ALK4)]. Transfection of a constitutively active form of the receptor, ALK4T206D, stimulated FSHbeta mRNA levels. Overexpression of the inhibitory SMAD7 blocked this effect, as well as activin-stimulated FSHbeta transcription. Because SMAD7 functions by preventing access of SMAD2 and SMAD3 to ALK4, these data suggested that both activins and ALK4 require SMAD2 and/or SMAD3 to affect FSHbeta transcription. Consistent with this idea, activin A stimulated SMAD2 and SMAD3 phosphorylation and nuclear translocation within 5-10 min in LbetaT2 cells. Transient transfection of SMAD3, but not SMADs 1, 2, 4, 5, or 8, stimulated endogenous FSHbeta mRNA levels. The results of SMAD2 transfection studies were inconclusive, however, because of a persistent failure to overexpress the full-length SMAD2 protein specifically in LbetaT2 cells. To assess more directly roles for both SMAD2 and SMAD3 in activin-stimulated FSHbeta expression, RNA interference was used to decrease endogenous SMAD protein levels in LbetaT2 cells. Activin A- and ALK4T206D-stimulated transcription of the FSHbeta gene were significantly attenuated by the depletion of either SMAD2 or SMAD3. Collectively, these data suggest that activins use both SMAD2- and SMAD3-dependent mechanisms to stimulate FSHbeta transcription in mouse gonadotrope cells.

Autoimmune thyroid disease--Hashimoto thyroiditis and Graves' disease--patients produce high levels of thyroid autoantibodies and contain lymphoid tissue that resembles secondary lymphoid follicles (LFs). We compared the specificity, structure, and function of tonsil and lymph node LFs with those of the intrathyroidal LFs to assess the latter's capability to contribute to autoimmune response. Thyroglobulin and thyroperoxidase binding to LFs indicated that most intrathyroidal LFs were committed to response to thyroid self-antigens and were associated to higher levels of antibodies to thyroglobulin, thyroperoxidase, and thyroid-stimulating hormone receptor. Intrathyroidal LFs were microanatomically very similar to canonical LFs, ie, they had well-developed germinal centers with mantle, light, and dark zones and each of these zones contained B and T lymphocytes, follicular dendritic and interdigitating dendritic cells with typical phenotypes. Careful assessment of proliferation (Ki67) and apoptosis (terminal dUTP nick-end labeling) indicators and of the occurrence of secondary immunoglobulin gene rearrangements (RAG1 and RAG2) confirmed the parallelism. Unexpected high levels of RAG expression suggested that receptor revision occurs in intrathyroidal LFs and may contribute to generate high-affinity thyroid autoantibodies. Well-formed high endothelial venules and a congruent pattern of adhesion molecules and chemokine expression in intrathyroidal LFs were also detected. These data suggest that ectopic intrathyroidal LFs contain all of the elements needed to drive the autoimmune response and also that their microenvironment may favor the expansion and perpetuation of autoimmune response.

Because the ovarian response to FSH stimulation in assisted reproduction is variable, ranging from hyporesponse to hyperresponse, with the possible complication of ovarian hyperstimulation, it would be of great benefit to predict the response of the patients to FSH. To date, no clear-cut predictors of ovarian responsiveness to FSH have been identified. In this study, we investigated the role of two distinct FSH receptor (FSHR) variants, Thr307/Asn680 and Ala307/Ser680, in the response to FSH in women undergoing controlled ovarian stimulation. The FSHR polymorphism at position 680 was analyzed by restriction-fragment-length polymorphism in 161 ovulatory women below the age of 40 yr. With reference to the couple, infertility has been diagnosed as being attributable to male causes (76%), tubal factor (11%), or both (13%). The distribution was 29% for the Asn/Asn, 45% for the Asn/Ser, and 26% for the Ser/Ser FSHR variant. Peak estradiol levels, number of preovulatory follicles, and number of retrieved oocytes were similar in the 3 groups. However, basal FSH levels were significantly different among the 3 groups (6.4 +/- 0.4 IU/L, 7.9 +/- 0.3 IU/L, and 8.3 +/- 0.6 IU/L for the Asn/Asn, Asn/Ser, and Ser/Ser groups, respectively, P < 0.01). The number of FSH ampoules required for successful stimulation was significantly different among the 3 groups (31.8 +/- 2.4, 40.7 +/- 2.3, and 46.8 +/- 5.0 for the Asn/Asn, Asn/Ser, and Ser/Ser groups, respectively, P < 0.05). According to multiple linear regression analysis, the number of ampoules needed could be predicted from a linear combination of both the type of polymorphism and basal FSH levels (P < 0.001). These clinical findings demonstrate that the ovarian response to FSH stimulation depends on the FSHR genotype.

BACKGROUND

The influence of elevated serum progesterone levels during in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles on pregnancy rates is a matter of continued debate among fertility clinicians. Efforts to resolve this question have been impeded by the various assays used to measure progesterone and the different, arbitrary threshold values for defining 'high' progesterone levels.

METHODS

A non-interventional, retrospective, observational, single-centre cohort study evaluated the relationship between serum progesterone levels on the day of human chorionic gonadotrophin (hCG) administration and the ongoing pregnancy rate in 4032 patients undergoing IVF/ICSI cycles using gonadotrophin-releasing hormone (GnRH) analogues for pituitary down-regulation.

RESULTS

Ongoing pregnancy rates were inversely associated with serum progesterone levels on the day of hCG (P < 0.001 for overall trend), irrespective of the GnRH analogue used for pituitary down-regulation. Patients with serum progesterone levels < or = 1.5 ng/ml had significantly higher ongoing pregnancy rates than those with progesterone levels >1.5 ng/ml (31.0 versus 19.1%; P = 0.00006); odds ratio, 0.53 (95% confidence interval, 0.38-0.72). Multivariate regression analysis showed that daily follicle-stimulating hormone dose, number of oocytes and estradiol values on the day of hCG administration were positively associated with progesterone levels (P < 0.0001 for all). Serum progesterone levels were significantly greater in women treated with GnRH agonists (n = 1177) versus antagonists (n = 2855; 0.84 +/- 0.67 versus 0.75 +/- 0.66 ng/ml; P = 0.0003).

CONCLUSIONS

Elevated serum progesterone levels on the day of hCG administration is associated with reduced ongoing pregnancy rates. In particular, serum progesterone levels of >1.5 ng/ml were associated with lower ongoing pregnancy rates following IVF/ICSI cycles irrespective of the GnRH analogue used for pituitary down-regulation.

Di-(2-ethylhexyl) phthalate (DEHP) is a known reproductive toxicant and a carcinogen in rodent animal models. DEHP may also be a reproductive toxicant in women. Its action in female animal models is undetermined, although its potential to target the ovary has recently been shown. We have identified the ovarian toxicity and target cells of DEHP in the female rat. Adult, regularly cycling Sprague-Dawley rats were dosed daily with 2 g/kg DEHP in corn oil by gavage for 1 to 12 days. Ovarian morphology and serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, and progesterone levels were analyzed. DEHP exposure resulted in prolonged estrous cycles. Specifically, 35 of 42 DEHP-treated rats had 5- or 6-day cycles and only 7 of 42 had a 4-day cycle compared to 44 of 45 control rats with 4-day cycle lengths. DEHP treatment also suppressed or delayed ovulations by the first proestrus/estrus after metestrus-initiated dosing. Microscopic evaluation of the ovaries determined that 7 of 10 DEHP-exposed rats had not ovulated by vaginal estrus, whereas 13 of 13 control rats had ovulated by vaginal estrus. Thus, DEHP treatment significantly altered natural ovulation times. Preovulatory follicles were also quantitatively smaller in DEHP-exposed rats than in controls because the granulosa cells were smaller. The mean control rat preovulatory follicle granulosa cell area was 16 +/- 3 x 10(3) microns, whereas the mean DEHP-treated rat preovulatory follicle granulosa cell area was 12 +/- 4 x 10(3) microns. DEHP exposure significantly suppressed preovulatory follicle granulosa cell estradiol production over 8 days of exposure. Suppressed serum estradiol levels caused secondary increases in FSH levels and did not stimulate the LH surge necessary for ovulation. Consequently, ovulation did not occur in DEHP-treated rats, although DEHP-treated rats ovulated after treatment with human chorionic hormone. Vaginal lavage cytology from rats treated with DEHP did not detect the ovarian toxicity as shown by histology and hormone analysis. In summary, exposure to DEHP resulted in hypoestrogenic anovulatory cycles and polycystic ovaries in adult female rats.

The fundamental aspects of the hypothalamic luteinizing hormone-releasing hormone (LHRH)(1) [1]pulse generator-pituitary gonadotrophin-gonadal apparatus in mammals have striking commonalities. There are, however, critical, substantive differences in the neuroendocrinology of puberty among species. The onset of puberty in the human is marked by an increase in the amplitude of LH pulses, an indirect indicator of the increase in amplitude of LHRH pulses. The hypothalamic LHRH-pituitary gonadotrophin complex is functional by at least 0.3 gestation in the human foetus; the sex difference in the fetal and neonatal pattern of LH and FSH secretion is an apparent consequence of imprinting of the fetal hypothalamus-pituitary-gonadotropin apparatus by fetal testosterone. Until about 6 months of age in boys and 12-24 months in girls, the testes and ovaries respond to the increased LH in boys and follicle-stimulating hormone (FSH) in girls by secreting testosterone and oestradiol, respectively, reaching levels that are not again achieved before the onset of puberty. Striking features of the ontogeny of the human hypothalamic pulse generator are: (1) its development and function in the foetus; (2) the continued function of the hypothalamic LHRH pulse generator-pituitary gonadotrophin-gonadal axis in infancy; (3) the gradual damping of hypothalamic LHRH oscillator activity during late infancy; (4) its quiescence during childhood - the so-called juvenile pause; (5) during late childhood the gradual disinhibition and reactivation of the LHRH pulse generator, mainly at night; (6) the increasing amplitude of the LHRH pulses, which are reflected in the progressively increased and changing pattern of circulating LH pulses, with the approach of and during puberty. The intrinsic central nervous system (CNS) mechanisms responsible for the inhibition of the LHRH pulse generator during childhood (the juvenile phase) involve the major role of an inhibitory neuronal system - the CNS inhibitory neurotransmitter gamma-aminobutyric acid (GABA) and GABAergic neurons, as revealed by studies in the rhesus monkey by Terasawa and her associates. With the onset of puberty, the disinhibition and reactivation of the LHRH pulse generator is associated with a fall in GABAergic neurotransmission and a concomitant increase in the input of excitatory amino acid neurotransmitters (including glutamate) and possibly astroglial-derived growth factors. Despite remarkable progress over the past three decades, large gaps remain in our understanding of the neurobiological, genetic and environmental mechanisms involved in the control of the onset of puberty. The role of leptin in the control of the onset of puberty is reviewed. Severe leptin deficiency is associated with hypogonadotrophic hypogonadism; it appears that a critical level of leptin and a leptin signal is required to achieve puberty. The weight of evidence supports the hypothesis that leptin acts as one of several permissive factors and not a trigger in the onset of human puberty. The application of these advances provides a framework for the described classification of sexual precocity and delayed puberty.1 GnRH is synonymous with LHRH.

Spermatogenesis is a complex process involving mitotic cell division, meiosis and the process of spermiogenesis. The regulation of spermatogenesis involves both endocrine and paracrine mechanisms. The endocrine stimulation of spermatogenesis involves both follicle stimulating hormone (FSH) and luteinizing hormone, the latter acting through the intermediary testosterone, produced by the Leydig cells in the testis. Since the germ cells do not possess receptors for FSH and testosterone, the hormonal signals are transduced through the Sertoli cells and peritubular cells by the production of signals that have yet to be defined. Although the hormonal signals are essential for successful spermatogenesis, there is increasing evidence that a multiplicity of growth factors and cytokines are involved in local control mechanisms influencing stem cell renewal by mitosis and the complicated process of the two meiotic cell divisions. The final complex metamorphosis which converts a round cell into the complex structures of the spermatozoa is well defined at a structural level, but the control systems regulating this process still remain to be elucidated.

BACKGROUND

Ovarian failure is a common toxic effect of chemotherapy. Studies of the use of gonadotropin-releasing hormone (GnRH) agonists to protect ovarian function have shown mixed results and lack data on pregnancy outcomes.

METHODS

We randomly assigned 257 premenopausal women with operable hormone-receptor-negative breast cancer to receive standard chemotherapy with the GnRH agonist goserelin (goserelin group) or standard chemotherapy without goserelin (chemotherapy-alone group). The primary study end point was the rate of ovarian failure at 2 years, with ovarian failure defined as the absence of menses in the preceding 6 months and levels of follicle-stimulating hormone (FSH) in the postmenopausal range. Rates were compared with the use of conditional logistic regression. Secondary end points included pregnancy outcomes and disease-free and overall survival.

RESULTS

At baseline, 218 patients were eligible and could be evaluated. Among 135 with complete primary end-point data, the ovarian failure rate was 8% in the goserelin group and 22% in the chemotherapy-alone group (odds ratio, 0.30; 95% confidence interval [CI], 0.09 to 0.97; two-sided P=0.04). Owing to missing primary end-point data, sensitivity analyses were performed, and the results were consistent with the main findings. Missing data did not differ according to treatment group or according to the stratification factors of age and planned chemotherapy regimen. Among the 218 patients who could be evaluated, pregnancy occurred in more women in the goserelin group than in the chemotherapy-alone group (21% vs. 11%, P=0.03); women in the goserelin group also had improved disease-free survival (P=0.04) and overall survival (P=0.05).

CONCLUSIONS

Although missing data weaken interpretation of the findings, administration of goserelin with chemotherapy appeared to protect against ovarian failure, reducing the risk of early menopause and improving prospects for fertility. (Funded by the National Cancer Institute and others; POEMS/S0230 ClinicalTrials.gov number, NCT00068601.).

Proteins in the TGF-beta superfamily transduce their effects through binding to type I and type II serine/threonine kinase receptors. Osteogenic protein-1 (OP-1, also known as bone morphogenetic protein-7 or BMP-7), a member of the TGF-beta superfamily which belongs to the BMP subfamily, was found to bind activin receptor type I (ActR-I), and BMP receptors type IA (BMPR-IA) and type IB (BMPR-IB) in the presence of activin receptors type II (ActR-II) and type IIB (ActR-IIB). The binding affinity of OP-1 to ActR-II was two- to threefold lower than that of activin A. A transcriptional activation signal was transduced after binding of OP-1 to the complex of ActR-I and ActR-II, or that of BMPR-IB and ActR-II. These results indicate that ActR-II can act as a functional type II receptor for OP-1, as well as for activins. Some of the known biological effects of activin were observed for OP-1, including growth inhibition and erythroid differentiation induction. Compared to activin, OP-1 was shown to be a poor inducer of mesoderm in Xenopus embryos. Moreover, follistatin, an inhibitor of activins, was found to inhibit the effects of OP-1, if added at a 10-fold excess. However, certain effects of activin, like induction of follicle stimulating hormone secretion in rat pituitary cells were not observed for OP-1. OP-1 has overlapping binding specificities with activins, and shares certain but not all of the functional effects of activins. Thus, OP-1 may have broader effects in vivo than hitherto recognized.

Activation of the RAS family of small G-proteins is essential for follicle stimulating hormone-induced signaling events and the regulation of target genes in cultured granulosa cells. To analyze the functions of RAS protein in granulosa cells during ovarian follicular development in vivo, we generated conditional knock-in mouse models in which the granulosa cells express a constitutively active KrasG12D. The KrasG12D mutant mice were subfertile and exhibited signs of premature ovarian failure. The mutant ovaries contained numerous abnormal follicle-like structures that were devoid of mitotic and apoptotic cells and cells expressing granulosa cell-specific marker genes. Follicles that proceeded to the antral stage failed to ovulate and expressed reduced levels of ovulation-related genes. The human chorionic gonadotropin-stimulated phosphorylation of ERK1/2 was markedly reduced in mutant cells. Reduced ERK1/2 phosphorylation was due, in part, to increased expression of MKP3, an ERK1/2-specific phosphatase. By contrast, elevated levels of phospho-AKT were evident in granulosa cells of immature KrasG12D mice, even in the absence of hormone treatments, and were associated with the progressive decline of FOXO1 in the abnormal follicle-like structures. Thus, inappropriate activation of KRAS in granulosa cells blocks the granulosa cell differentiation pathway, leading to the persistence of abnormal non-mitotic, non-apoptotic cells rather than tumorigenic cells. Moreover, those follicles that reach the antral stage exhibit impaired responses to hormones, leading to ovulation failure. Transient but not sustained activation of RAS in granulosa cells is therefore crucial for directing normal follicle development and initiating the ovulation process.

Bone remodeling rates (Ac.f) were measured in transilial biopsy specimens from 50 healthy premenopausal women before and 1 year after menopause, in 34 healthy women 13 years past menopause, and in 89 women with untreated osteoporosis. Ac.f nearly doubled 1 year after menopause, tripled 13 years after menopause, and remained elevated in women with osteoporosis.

BACKGROUND

Increased bone remodeling rates are associated with increased skeletal fragility independent of bone mass, partially accounting for the age-related increase in fracture risk in women that is independent of bone loss. We examined bone remodeling rates before and after menopause and in women with osteoporosis by measurements of activation frequency (Ac.f, #/year) in transilial bone biopsy specimens.

METHODS

We recruited 75 women,>> 46 years old, who had premenopausal estradiol and gonadotropin levels and regular menses. During 9.5 years of observation, 50 women experienced normal menopause and had 2 transilial bone biopsy specimens after tetracycline labeling, one at the beginning of observation and the second 12 months after the last menses, when serum follicle-stimulating hormone (FSH) was>> 75 mIU/ml and serum estradiol was < 20 pg/ml. Ac.f was also computed for a group of older healthy postmenopausal women and a group of women with untreated osteoporosis studied earlier by the same biopsy (Bx) and labeling protocol.

RESULTS

Median Ac.f rose from 0.13/year to 0.24/year (p < 0.001) across menopause and was greater still in the older normals (p < 0.008) than in the second Bx. Ac.f was not significantly greater in the osteoporosis patients than in the older postmenopausal normals.

CONCLUSIONS

Bone remodeling rates double at menopause, triple 13 years later, and remain elevated in osteoporosis. This change contributes to increases in age-related skeletal fragility in women.

Hypothalamic peptide hormones regulate the secretion of most of the anterior pituitary hormones, that is, growth hormone, follicle-stimulating hormone, luteinizing hormone, thyroid-stimulating hormone and adrenocorticotropin. These peptides do not regulate the secretion of prolactin, at least in a specific manner, however. The peptides act through specific receptors, which are referred to as seven-transmembrane-domain receptors or G-protein-coupled receptors. Although prolactin is important in pregnancy and lactation in mammals, and is involved in the development of the mammary glands and the promotion of milk synthesis, a specific prolactin-releasing hormone has remained unknown. Here we identify a potent candidate for such a hormone. We first proposed that there may still be unknown peptide hormone factors that control pituitary function through seven-transmembrane-domain receptors. We isolated the complementary DNA encoding an 'orphan' receptor (that is, one for which the ligand is unknown). This receptor, hGR3, is specifically expressed in the human pituitary. We then searched for the hGR3 ligand in the hypothalamus and identified a new peptide, which shares no sequence similarity with known peptides and proteins, as an endogenous ligand. We show that this ligand is a potent prolactin-releasing factor for rat anterior pituitary cells; we have therefore named this peptide prolactin-releasing peptide.