Follicle-stimulating hormone (FSH) regulation of aromatase gene expression in vitro requires the transcriptional coactivator beta-catenin. To ascertain the physiological significance of beta-catenin in granulosa cells during folliculogenesis, mice homozygous for floxed alleles of beta-catenin were intercrossed with Amhr2cre mice. Conditional deletion of beta-catenin in 8-wk-old females occurred in derivatives of the Müllerian duct, granulosa cells and, surprisingly, in brain, pituitary, heart, liver, and tail. Female mice deficient for beta-catenin were infertile, despite reaching puberty and ovulating at the expected age, indications of apparently normal ovarian function. In contrast, their oviducts were grossly distended, with fewer but healthy oocytes. In addition, their uteri lacked implantation sites. Together, these two phenotypes could explain the complete loss of fertility. Nevertheless, although the ovary appeared normal, with serum estradiol concentrations in the normal range, there was marked animal-to-animal variation of mRNAs encoding beta-catenin and aromatase. Similarly, inhibin-alpha and luteinizing hormone receptor mRNAs varied considerably in whole ovaries, whereas pituitary Fshb mRNA was significantly reduced. Collectively, these features suggested cyclization recombination (CRE)-mediated recombination of beta-catenin may be unstable in proliferating granulosa cells, and therefore may mask the suspected steroidogenic requirement for beta-catenin. We tested this possibility by transducing primary cultures of granulosa cells from mice homozygous for floxed alleles of beta-catenin with a CRE-expressing adenovirus. Reduction of beta-catenin significantly compromised FSH stimulation of aromatase mRNA and subsequent production of estradiol. Collectively, these data suggest that FSH regulation of steroidogenesis requires beta-catenin, a role that remains hidden when tested through Amhr2cre-mediated recombination in vivo.

The present study examined whether the rates of oocyte maturation, fertilization and development, as well as pregnancy rate could be improved by human chorionic gonadotrophin (HCG) priming 36 h before immature oocyte retrieval in patients with polycystic ovarian syndrome (PCOS). Immature oocyte retrieval was performed on day 10-14 of the cycles and patients were randomly allocated either to be primed with 10 000 IU of HCG before the retrieval, or not primed. Immature oocytes were cultured for 24-48 h in TC-199 medium with 20% (v/v) inactivated fetal bovine serum (FBS) supplemented with 75 mIU/ml follicle stimulating hormone (FSH) and luteinizing hormone (LH). Intracytoplasmic sperm injection (ICSI) was performed in all mature oocytes and the resulting embryos were transferred on day 2 or 3 after ICSI. A total of 17 patients underwent 24 completed treatment cycles. Thirteen cycles were primed with HCG and 11 other cycles were not primed. The mean number of oocytes retrieved was comparable in the two groups (7.8 +/- 3.9 versus 7.4 +/- 5.2). The percentage of oocytes achieving maturation at 48 h was significantly higher (P < 0.05) in the HCG-primed group (84.3%, 86/102) than in the non-HCG-primed group (69.1%, 56/81). Oocyte maturation was hastened in the HCG-primed group. Following 24 h of culture, 78.2 +/- 7.1% of oocytes were matured in the HCG-primed group compared with 4.9 +/- 2.5% of oocytes in the non-HCG-primed group (P < 0.001). There were no significant differences in the rates of oocyte fertilization and cleavage in these two groups. There were five clinical pregnancies (38.5%) in the HCG-primed group, and three pregnancies (27.3%) in the non-HCG-primed group.

Neurohormones similar to those of mammals are carried in fish by hypothalamic nerve fibers to regulate directly follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Gonadotropin-releasing hormone (GnRH) stimulates the secretion of FSH and LH and the expression of the glycoprotein hormone alpha (GPalpha), FSHbeta, and LHbeta, as well as their secretion. Its signal transduction leading to LH release is similar to that in mammals although the involvement of cyclic AMP-protein kinase A (cAMP-PKA) cannot be ruled out. Dopamine (DA) acting through DA D2 type receptors may inhibit LH release, but not that of FSH, at sites distal to activation of protein kinase C (PKC) and PKA. GnRH increases the steady-state levels of GPalpha, LHbeta, and FSHbeta mRNAs. Pituitary adenylate cyclase-activating polypeptide (PACAP) 38 and neuropeptide Y (NPY) potentiate GnRH effect on gonadotropic cells, and also act directly on the pituitary cells. Whereas PACAP increases all three subunit mRNAs, NPY has no effect on that of FSHbeta. The effect of these peptides on the expression of the gonadotropin subunit genes is transduced differentially; GnRH regulates GPalpha and LHbeta via PKC-ERK and PKA-ERK cascades, while affecting the FSHbeta transcript through a PKA-dependent but ERK-independent cascade. The signals of both NPY and PACAP are transduced via PKC and PKA, each converging at the ERK level. NPY regulates only GPalpha- and LHbeta-subunit genes whereas PACAP regulates the FSHbeta subunit as well. Like those of the mammalian counterparts, the coho salmon LHbeta gene promoter is driven by a strong proximal tripartite element to which three different transcription factors bind. These include Sf-1 and Pitx-1 as in mammals, but the function of the Egr-1 appears to have been replaced by the estrogen receptor (ER). The GnRH responsive region in tilapia FSHbeta 5' flanking region spans the canonical AP1 and CRE motifs implicating both elements in conferring GnRH responsiveness. Generally, high levels of gonadal steroids are associated with high LHbeta transcript levels whereas those of FSHbeta are reduced when pituitary cells are exposed to high steroid levels. Gonadal or hypophyseal activin also participate in the regulation of FSHbeta and LHbeta mRNA levels. However, gonadal effects are dependent on the gender and stage of maturity of the fish.

OBJECTIVE

To generate estimates of the association between markers of ovarian aging and natural fertility in a community sample at risk for ovarian aging.

METHODS

Women aged 30-44 years with no history of infertility who had been trying to conceive for less than 3 months provided early-follicular phase serum and urine (N=100). Subsequently, these women kept a diary to record menstrual bleeding and intercourse and conducted standardized pregnancy testing for up to 6 months. Serum was analyzed for estradiol, follicle-stimulating hormone (FSH), antimüllerian hormone, and inhibin B. Urine was analyzed for FSH and estrone 3-glucuronide. Diary data on menstrual cycle day and patterns of intercourse were used to calculate day-specific fecundability ratios.

RESULTS

Sixty-three percent of participants conceived within 6 months. After adjusting for age, 18 women (18%) with serum antimüllerian hormone levels of 0.7 ng/mL or less had significantly reduced fecundability given intercourse on a fertile day compared with women with higher antimüllerian hormone levels (fecundability ratio 0.38; 95% confidence interval [CI] 0.08-0.91). The day-specific fecundability for women with early-follicular phase serum FSH values greater than 10 milli-international units/mL compared with women with lower FSH levels was also reduced, although nonsignificantly (11% of women affected; fecundability ratio 0.44; 95% CI 0.08-1.10). The association with urinary FSH was weaker (27% women affected; fecundability ratio 0.61; 95% CI 0.26-1.26), and the associations for the other markers were weaker still.

CONCLUSIONS

Early-follicular phase antimüllerian hormone appears to be associated with natural fertility in the general population.

METHODS

II.

A clomiphene citrate (CC) challenge test was used to prospectively assess future fertility potential in 51 women aged 35 or more with unexplained infertility. Baseline (day 2-3 of the menstrual cycle) and response levels (day 9-11) of follicle stimulating hormone (FSH), luteinising hormone (LH), and 17-beta oestradiol were measured before and after administration of 100 mg clomiphene on days 5-9 of the menstrual cycle. Although all the women had a normal baseline FSH, 18 had an exaggerated FSH response of 26 mIU/ml or more (over 2 standard deviations above control values); this was regarded as a diminished ovarian reserve (DOR). In the DOR group mean response FSH was 38.9 mIU/ml (SD 13.8) and in 33 women with adequate ovarian reserve (AOR) it was 11.5 (4.9) mIU/ml (p less than 0.0001). In the DOR group 1 of 18 patients and in the AOR group 14 of 33 (42%) conceived (p less than 0.05). It is suggested that despite apparently normal ovulatory cycles, the DOR group has a compromised follicular apparatus. Disparity between normal oestradiol secretory capacity of the granulosa and diminished capacity to secrete inhibin could explain the inappropriately high FSH levels in response to the CC challenge.

The menstrual cycle in women is characterised by high variability in cycle length (26-35 days), 5-day menses, a fertile phase from 5 days before to the day of ovulation, and low fertility which is dependent on cycle length and age. All women show an FSH rise at the luteal-follicular transition, stimulating a cohort of follicular growth and inhibin B secretion in the early follicular phase. The ovulatory dominant follicle (DF) is selected in the mid-follicular phase, and as this DF grows it increasingly secretes oestradiol and inhibin A for a week before ovulation. Gonadotrophin responsiveness, IGF binding protein expression and degradation, and vascularisation have been identified to be crucial for DF selection and progression. Two-thirds of women show two follicle waves and 1/3 show 3 follicle waves per cycle. Three-wave women have longer cycles, and a later oestradiol rise and LH surge. The corpus luteum secretes progesterone, oestradiol and inhibin A in response to LH pulses, and reaches its peak in terms of size, secretions, and vascularization 6-7 days after ovulation. Luteal regression is passive and independent of the uterus, but can be prevented by hCG, the luteotrophic signal from the trophoblast, from 8 days after conception. Reductions in systemic steroid and protein hormone concentrations may be responsible for the FSH rise characteristic of premenopausal women. The functional layer of the endometrium shows steroid hormone-dependent proliferation, differentiation, and shedding in the absence of the trophoblast. Menstruation is initiated by progesterone responsive decidual cells, and executed by PGE and PGF2α, vasoconstriction and matrix metalloprotease secretion by leukocytes. Ovarian function and also hormone fluctuations during the menstrual cycle are similar to oestrous cycles of cows and mares, justifying research into comparative aspects of menstrual and oestrous cycles in monovulatory species.

BACKGROUND

Large artery mechanical properties are a major determinant of pulse pressure and cardiovascular outcome. Sex differences in these properties may underlie the variation in cardiovascular risk profile between men and women, in relation to age.

OBJECTIVE

To investigate sex differences in the age-related stiffening of large arteries.

METHODS

Cross-sectional.

METHODS

One hundred and twenty healthy men and women were recruited and divided equally into tertiles by age: young (mean +/- SD, 23 +/- 5 years), middle-age (47 +/- 3 years) and older (62 +/- 7 years). Lipids, mean arterial pressure and heart rate were matched within each tertile. Carotid tonometry and Doppler velocimetry were used to measure indices of large artery stiffness.

RESULTS

There was no sex difference in systemic arterial compliance (SAC) in the young group (mean +/- SEM, 0.61 +/- 0.05 arbitrary compliance units (ACU) in women compared with 0.67 +/- 0.04 ACU in men), but in the older population women had lower SAC than men (0.27 +/- 0.03 ACU compared with 0.57 +/- 0.04 ACU respectively; P < 0.001). Measures independent of aortic geometry (distensibility index and aortic impedance) indicated that stiffness was lower in young women than in men (P < 0.05), but the reverse was true in the older population (P < 0.01). This paralleled the brachial and carotid pulse pressures, which were lower in young (P < 0.01) and higher in older women compared with those in men (P < 0.05). Follicle stimulating hormone concentrations correlated strongly (r values 0.39-0.65) with all indices of central, but not peripheral, arterial function, whereas concentrations of luteinizing hormone, progesterone and oestradiol correlated less strongly.

CONCLUSIONS

In men and women matched for mean pressures, the age-related stiffening of large arteries is more pronounced in women, which is consistent with changes in female hormonal status.

The efficacy of recombinant human LH (rhLH) for supporting human (rhFSH)-induced follicular development was investigated in hypogonadotropic hypogonadal women (WHO group I anovulation). Patients (n = 38) were randomized to receive rhLH (0, 25, 75, or 225 IU/day) in addition to a fixed dose of rhFSH (150 IU/day). rhLH was found 1) to promote dose-related increases in estradiol (E2) and androstenedione secretion by rhFSH-induced follicles, i.e. serum concentrations on the last day of FSH administration were 65 +/- 4, 195 +/- 94, 1392 +/- 585, and 2441 +/- 904 pmol/L for E2 and 3.6 +/- 0.9, 5.1 +/- 1.3, 6.4 +/- 1.3, and 6.7 +/- 1.3 nmol/L for androstenedione for patients treated with 0, 25, 75, and 225 IU rhLH, respectively; 2) to increase ovarian sensitivity to FSH, as demonstrated by the proportion of patients who developed follicles after the administration of a fixed dose of FSH, i.e. 1 of 8, 3 of 7, 7 of 9, and 8 of 10 in patients treated with 0, 25, 75, and 225 IU rhLH, respectively; and 3) to enhance the ability of these follicles to luteinize when exposed to hCG. A daily dose of 75 IU rhLH was effective in the majority of women in promoting optimal follicular development (defined as>> or = 1 follicle>> or = 17 mm; E2,>> or = 400 pmol/L; midluteal phase progesterone,>> or = 25 nmol/L) and maximal endometrial growth. A minority of patients may require up to 225 IU/day. rhLH, given sc at a dose up to 225 IU/day, was not immunogenic and was well tolerated.

Late results were determined for 42 patients who had undergone detorsion and fixation for unilateral testicular torsion in the prepubertal and pubertal age. Exocrine and endocrine function for the testes was determined in 30 patients who had reached postpuberal age. Patients who underwent detorsion and fixation 8 hours or less after the onset of symptoms had normal-sized testicles and only slight changes in testicular morphology. When treatment was delayed and detorsion was done more than 8 hours later a marked decrease was observed in testicular size. The exocrine function in patients with torsion was reduced. The semen quality, as judged by 2 semen analyses, was normal in 15 patients, doubtful in 3 and pathological in 12. Even when detorsion was done 4 hours or less after the onset of symptoms the exocrine function of the testes was normal in only 50 per cent of the cases. In patients with doubtful and pathological sperm analyses higher follicle-stimulating and luteinizing hormone levels were observed.

OBJECTIVE

To determine whether gonadotropin levels are elevated in patients with Alzheimer disease (AD).

METHODS

We measured luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels from stored plasma samples from 284 patients seen at a tertiary care center. We also reviewed their medical charts to record age and estrogen use in the women. The primary aim of our study was to determine whether gonadotropin levels were elevated in 134 patients with AD compared with levels from 45 patients with frontotemporal dementia (FTD) and 105 cognitively normal controls.

RESULTS

Although overlap between LH and FSH levels was considerable, LH (P=.046) and FSH (P=.007) were significantly elevated in estrogen-free women with AD (LH: median, 26.3 IU/L; interquartile range, 14.9-34.6 IU/ L; FSH: median, 62.0 IU/L; interquartile range, 45.9-78.5 IU/L) compared with normal controls (LH: median, 20.1 IU/L; interquartile range, 13.7-25.3 IU/L; FSH: median, 47.7 IU/L; interquartile range, 34.1-57.5 IU/L). Levels of LH were also significantly higher (P=.03) in estrogen-free women with AD compared with women with FTD (LH: median, 20.7 IU/L; interquartile range, 19.0-28.5 IU/L; FSH: median, 53.3 IU/L; interquartile range, 27.6-77.9 IU/ L). When we controlled for age, no differences in LH and FSH were observed in men with AD compared with normal controls.

CONCLUSIONS

Gonadotropin levels are elevated in some patients with AD, ie, women not taking estrogen. Elevated gonadotropin levels may have a role in the production of amyloid-beta protein, which is related to formation of senile plaques. Therefore, elevated gonadotropin levels may be involved in the pathogenesis of AD.

Clonidine (0.15 mg iv), a selective noradrenergic receptor agonist, increased serum growth hormone (GH) levels (greater than 6 ng/ml) on 8 out of 12 administrations to 6 normal men. This increase was independent of the hypotensive effects of the drug and unrelated to changes in serum cortisol. Clonidine induced a hyperglycemic effect in all subjects which was greatest 15 min after commencint the injection. No changes in blood sugar or GH occurred after placebo injection. Apomorphine, a selective dopamine receptor agonist, elevated GH in each of these 6 subjects (greater than 10 ng/ml). Clonidine had no effect on serum prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), or thyroid-stimulating hormone (TSH). These data are compatible with a dual dopaminergic and noradrenergic mechanism modulating GH secretion in normal men and with the absence of a noradrenergic mechanism in the regulation of PRL, LH, FSH, or TSH.

The purpose of this study was to determine whether basal or stimulated (or both) serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) on day 3 of the cycle before administration of exogenous gonadotropins can predict stimulation response and in vitro fertilization (IVF) outcome. Eighty consecutive new patients underwent a gonadotropin-releasing hormone (GnRH) stimulation test on the morning of cycle day 3. All patients underwent the same stimulation protocol consisting of a combination of FSH and human menopausal gonadotropin (hMG). Paired discriminant analysis of FSH0 (at 0 minutes from GnRH injection) and LH0 revealed seven distinct groups of patients with statistically significant differences among the means: groups 1, 2, and 3 (26.25%) with higher means FSH0:LH0; group 4 (40%) with mean FSH0:LH0 (both levels less than 10 mIU/ml) of 1:1, and groups 5, 6, and 7 (33.75%) with higher mean LH0:FSH0. Canonical discriminant analysis of both basal and stimulated serum FSH and LH levels confirmed the seven groups and did not add to the information from analysis of FSH0 and LH0 only. Serum estradiol (E2) response during stimulation, as well as the number of preovulatory oocytes aspirated and transferred, was highest in the groups with a higher mean LH0:FSH0, intermediate in the group with mean FSH0:LH0 of 1:1, and lowest in the group with a higher mean FSH0:LH0. No pregnancy occurred in the higher FSH:LH groups. It is concluded that basal serum gonadotropin levels can distinguish different populations of IVF patients who tend to behave differently in terms of E2 response, oocytes obtained and transferred, and pregnancy rates and outcome.

GnRH provides the primary stimulus for the reproductive axis, but original work also revealed the existence of a gonadotropin-inhibitory hormone (GnIH) in birds. In mammals, GnIH properties are displayed by a hypothalamic dodecapeptide, which is a member of the RF-amide family, namely RF-amide-related peptide (RFRP)-3. This peptide inhibits GnRH-stimulated gonadotropin secretion from ovine pituitary cells in culture, but it is not known whether there are effects on gonadotropin synthesis. The aim of the present study was to determine the effects of RFRP-3 on the expression of genes for beta-subunits of the gonadotropins in ovine pituitary cells from gonadectomized ewes and rams. Cells in primary culture were given GnRH or vehicle pulses every 8 h for 24 h with and without RFRP-3 treatment. GnRH stimulated LH and FSH secretion, which was reduced by RFRP-3. Quantitative real-time PCR revealed increased expression of LHbeta and FSHbeta subunit genes after GnRH treatment and a specific reduction in expression after RFRP-3 treatment. There was no effect on the expression of GH, proopiomelanocortin, or prolactin genes. Western blotting showed that GnRH stimulated phosphorylation of ERK (phospho-ERK-1/2), and this effect was abolished by RFRP-3. We conclude that RFRP-3 acts on the pituitary gonadotropes to inhibit synthesis of the gonadotropins, and this effect may be mediated by a reduction in the GnRH-stimulated second messenger phospho-ERK-1/2.

Exposure of female sheep fetuses to excess testosterone (T) during early to midgestation produces postnatal hypergonadotropism manifest as a selective increase in LH. This hypergonadotropism may result from reduced sensitivity to estradiol (E2) negative feedback and/or increased pituitary sensitivity to GnRH. We tested the hypothesis that excess T before birth reduces responsiveness of LH and FSH to E2 negative feedback after birth. Pregnant ewes were treated with T propionate (100 mg/kg in cotton seed oil) or vehicle twice weekly from d 30-90 gestation. Responsiveness to E2 negative feedback was assessed at 12 and 24 wk of age in the ovary-intact female offspring. Our experimental strategy was first to arrest follicular growth and reduce endogenous E2 by administering the GnRH antagonist (GnRH-A), Nal-Glu (50 microg/kg sc every 12 h for 72 h), and then provide a fixed amount of exogenous E2 via an implant. Blood samples were obtained every 20 min at 12 wk and every 10 min at 24 wk before treatment, during and after GnRH-A treatment both before and after E2 implant. GnRH-A ablated LH pulsatility, reduced FSH by approximately 25%, and E2 production diminished to near detection limit of assay at both ages in both groups. Prenatal T treatment produced a precocious and selective reduction in responsiveness of LH but not FSH to E2 negative feedback, which was manifest mainly at the level of LH/GnRH pulse frequency. Collectively, these findings support the hypothesis that prenatal exposure to excess T decreases postnatal responsiveness to E2 inhibitory feedback of LH/GnRH secretion to contribute to the development of hypergonadotropism.

BACKGROUND

Aromatase inhibitors (AI) are increasingly used in early breast cancer and there is a growing interest in associated long-term side-effects of profound estrogen suppression. Urogenital side-effects due to atrophic vaginitis are often managed with vaginal estrogen preparations. These are generally perceived to result in minimal systemic absorption of estrogen. We followed serum estradiol, follicle stimulating hormone (FSH) and luteinising hormone (LH) levels in seven postmenopausal women using vaginal estrogen preparations whilst on AIs for breast cancer.

METHODS

Serum was analysed for estradiol, FSH and LH at baseline then 2, 4, 7-10 and 12 weeks since commencement of vaginal estradiol. Estradiol was measured on an assay specifically developed for measuring low levels in postmenopausal women.

RESULTS

Serum estradiol levels rose from baseline levels < or = 5 pmol/l consistent with AI therapy to a mean 72 pmol/l at 2 weeks. By 4 weeks this had decreased to < 35 pmol/l in the majority (median 16 pmol/l) although significant further rises were seen in two women.

CONCLUSIONS

The vaginal estradiol tablet Vagifem significantly raises systemic estradiol levels, at least in the short term. This reverses the estradiol suppression achieved by aromatase inhibitors in women with breast cancer and is contraindicated.

OBJECTIVE

We investigated the efficacy and safety of degarelix treatment and the effects of switching from leuprolide to degarelix in an ongoing extension study with a median 27.5-month followup of a pivotal 1-year prostate cancer trial.

METHODS

Patients who completed a 1-year pivotal phase III trial continued on the same monthly degarelix maintenance dose (160 or 80 mg in 125 each), or were re-randomized from leuprolide 7.5 mg to degarelix 240/80 mg (69) or 240/160 mg (65). Data are shown on the approved degarelix 240/80 mg dose. The primary end point was safety/tolerability and the secondary end points were testosterone, prostate specific antigen, luteinizing hormone and follicle-stimulating hormone responses, and prostate specific antigen failure and progression-free survival.

RESULTS

During followup testosterone and prostate specific antigen suppression were similar to those in the 1-year trial in patients who continued on degarelix or switched from leuprolide. The prostate specific antigen progression-free survival hazard rate was decreased significantly after the switch in the leuprolide/degarelix group while the rate in those who continued on degarelix was consistent with the rate in treatment year 1. The same hazard rate change pattern occurred in the group with baseline prostate specific antigen greater than 20 ng/ml. Adverse event frequency was similar between the groups and decreased with time.

CONCLUSIONS

Data support the statistically significant prostate specific antigen progression-free survival benefit for degarelix over leuprolide seen during year 1 and the use of degarelix as first line androgen deprivation therapy as an alternative to a gonadotropin-releasing hormone agonist.

OBJECTIVE

The objective of the study was to identify menopause transition stages using acceleration or deceleration patterns of FSH rates of change from the late reproductive years to postmenopause.

METHODS

Participants were the Michigan Bone Health and Metabolism Study cohort of 629 women, aged 24-44 yr (in 1992/3), with 5757 annual FSH data points over a 14-yr period. DESIGN/MAIN OUTCOME MEASURES: The study was designed to relate acceleration/deceleration patterns in FSH rate of change to time to final menstrual period (FMP) and chronological age using nonparametric and piecewise regression modeling.

RESULTS

Four major FSH stages, based on rate of FSH change patterns, were identifiable in relation to the FMP. In FSH stage 1, the rate of FSH change increased modestly up to -7 yr prior to the FMP; in FSH stage 2 (-7 to -2 yr prior to FMP), there was a major acceleration in FSH rate of change. FSH stage 3 had an acute increase in FSH rate of change (-2 to +1 yr around the FMP), with average FSH level of 34 mIU/ml. The fourth, or plateau, FSH stage began at 1 yr after FMP when the average FSH level was 54 mIU/ml. During the yr 28-60, there were eight age-specific epochs defined by significant changes of FSH trajectory accelerations or decelerations and rate of change.

CONCLUSIONS

Four menopause transition stages bounding the FMP and eight epochs in chronological aging from age 28 to 60 yr were defined by changes of FSH trajectory accelerations/decelerations and rates of change. This timing information, combined with knowledge of FSH levels and menstrual cycle characteristics, can help discern the likely status of women with respect to their reproductive viability and menopause transition stage.

Selective synthesis and release of FSH from pituitary gonadotropes is regulated by activins. Activins directly stimulate murine FSHbeta (Fshb) subunit gene transcription through a consensus 8-bp Sma- and Mad-related protein-binding element (SBE) in the proximal promoter. In contrast, the human FSHB promoter is relatively insensitive to the direct effects of activins and lacks this SBE. The proximal porcine Fshb promoter, which is highly conserved with human, similarly lacks the 8-bp SBE, but is nonetheless highly sensitive to activins. We used a comparative approach to determine mechanisms mediating differential activin induction of human, porcine, and murine Fshb/FSHB promoters. We mapped an activin response element in the proximal porcine promoter and identified interspecies variation in a single base pair in close proximity that conferred strong binding of the forkhead transcription factor FOXL2 to the porcine, but not human or murine, promoters. Introduction of the human base pair into the porcine promoter abolished FOXL2 binding and activin A induction. FOXL2 conferred activin A induction to the porcine promoter in heterologous cells, whereas knockdown of the endogenous protein in gonadotropes inhibited the activin A response. The murine Fshb promoter lacks the high-affinity FOXL2-binding site, but its activin induction is FOXL2 sensitive. We identified a more proximal FOXL2-binding element in the murine promoter, which is conserved across species. Mutation of this site attenuated activin A induction of both the porcine and murine promoters. Collectively, the data indicate a novel role for FOXL2 in activin A-regulated Fshb transcription.

Previous studies have suggested that exposure to polychlorinated biphenyls (PCBs) may alter thyroid function, but data on effects of PCB exposure on other endogenous hormones has been lacking. The current study is ancillary to a larger investigation of the effects of Great Lakes fish consumption on PCBs and reproductive function. In the current study we examine associations of PCBs, 1,1-bis (4-chlorophenyl)-2,2-dichloroethene (DDE), and fish consumption with thyroid and steroid hormones in 178 men and PCBs, DDE, and fish consumption with thyroid hormones in 51 women from the original study. Serum PCB level and consumption of Great Lakes fish are associated with significantly lower levels of thyroxine (T(4)) and free thyroxine index (FTI) in women and with significantly lower levels of T(4) in men. Fish consumption, but not PCB level, is significantly and inversely associated with triiodothyronine (T(3)) in men. Results for thyroid-stimulating hormone (TSH) are inconsistent. Among men, there are significant inverse associations of both PCB and fish consumption with sex hormone-binding globulin (SHBG)-bound testosterone, but no association with SHBG or free testosterone. There are no significant overall associations of PCB, DDE, or fish consumption with estrone sulfate, follicle-stimulating hormone, luteinizing hormone, or dehydroepiandrosterone sulfate. The results of this study are consistent with previous studies showing effects of fish consumption and PCB exposure on thyroid hormones and suggest that PCBs may also decrease steroid binding to SHBG. Elucidation of specific mechanisms must await future investigations.

The present study aimed to identify selective androgen receptor modulators (SARMs) with in vivo pharmacological activity. We examined the in vitro and in vivo pharmacological activity of four chiral, nonsteroidal SARMs synthesized in our laboratories. In the in vitro assays, these compounds demonstrated moderate to high androgen receptor (AR) binding affinity, with K(i) values ranging from 4 to 37 nM, and three of the compounds efficaciously stimulated AR-mediated reporter gene expression. The compounds were then administered subcutaneously to castrated rats to appraise their in vivo pharmacological activity. Androgenic activity was evaluated by the ability of these compounds to maintain the weights of prostate and seminal vesicle, whereas levator ani muscle weight was used as a measure of anabolic activity. The maximal response (E(max)) and dose for half-maximal effect (ED(50)) were determined for each compound and compared with that observed for testosterone propionate (TP). Compounds S-1 and S-4 demonstrated in vivo androgenic and anabolic activity, whereas compounds S-2 and S-3 did not. The activities of S-1 and S-4 were tissue-selective in that both compounds stimulated the anabolic organs more than the androgenic organs. These two compounds were less potent and efficacious than TP in androgenic activity, but their anabolic activity was similar to or greater than that of TP. Neither S-1 nor S-4 caused significant luteinizing hormone or follicle stimulating hormone suppression at doses near the ED(50) value. Thus, compounds S-1 and S-4 were identified as SARMs with potent and tissue-selective in vivo pharmacological activity, and represent the first members of a new class of SARMs with selective anabolic effects.

In the present study rats were dosed from weaning, through puberty and gestation, to Day 15 of lactation with methoxychlor at 25, 50, 100, or 200 mg/kg/day. Morphological landmarks of puberty were measured, including the ages at vaginal opening, first estrus, and first estrous cycle in females and at preputial separation in males. In the female, estrous cyclicity, fertility, litter size, number of implantation sites, organ weights, and ovarian and uterine histology were also measured. The viability of the offspring (F1) and their fertility were evaluated using a continuous breeding protocol. Males were necropsied after breeding, the reproductive organs were weighed, and the cauda epididymal sperm counts were determined. One testis was used for histopathology, while the other was used to quantify interstitial fluid (IF) content, IF testosterone concentration, and testicular sperm production. Testosterone and androgen-binding protein were measured in the caput epididymis, and sperm motility and morphology were evaluated from a caudal sample. The serum and pituitary were saved for hormonal determinations. Methoxychlor accelerated the age at vaginal opening and first estrus, and the vaginal smears were cornified. Growth was retarded at 100 and 200 mg/kg/day and fertility was reduced when the females were bred with untreated or similarly treated males. In the highest-dose group, the mated females went from constant estrus into pseudopregnancy following mating, but they had no implants. In males, methoxychlor treatment markedly reduced growth, seminal vesicle weight, cauda epididymal weight, caudal sperm content, and pituitary weight. Puberty was delayed in the two highest-dosage groups. Testicular sperm measures were much less affected than caudal measures. Testis weight and histology were slightly affected, and testicular sperm production, sperm morphology, and motility were unaffected. Endocrine function of the testes and pituitary was altered by methoxychlor administration. Leydig cell testosterone production, in response to human chorionic gonadotropin challenge, was reduced and pituitary levels of prolactin, thyroid-stimulating hormone (TSH), and follicle-stimulating hormone (FSH) were altered. In contrast, serum levels of prolactin, FSH, and luteinizing hormone were unaffected. Serum TSH was reduced by 50% of control at 100 and 200 mg/kg/day, while pituitary levels were increased. Gonadotropin-releasing hormone concentration in the mediobasal hypothalamus was also elevated. In spite of the many reproductive alterations, the fertility of treated males was not reduced when they were mated with untreated females.(ABSTRACT TRUNCATED AT 400 WORDS)

BACKGROUND

Longitudinal clinical studies demonstrate that increases in bone turnover that occur in perimenopausal women correlate better with elevated serum FSH than with changes in serum estradiol (E2). This perimenopausal rise in FSH is due to a selective decrease in ovarian inhibin B (InhB). Our previous demonstration that inhibins suppress both osteoblast and osteoclast development suggests that changes in serum inhibins may regulate osteoblast and osteoclast differentiation and thereby bone turnover, independent of changes in sex steroids.

OBJECTIVE

The objective of this study was to determine whether decreased serum inhibin A (InhA) and InhB levels correlate with increases in markers of bone turnover in women across the menopause transition and to evaluate serum inhibins as better predictors of bone turnover markers across the menopause transition than FSH or bioavailable E2.

METHODS

We studied a cross-sectional age-stratified population sample of 188 pre- and postmenopausal women not using oral contraceptives or hormone replacement therapy (age, 21-85 yr).

RESULTS

Serum InhA and InhB levels significantly correlated inversely with markers of bone formation and bone resorption in pre- and perimenopausal women and with markers of bone formation in postmenopausal women (InhA only). FSH was not significantly correlated with bone turnover in either pre- or postmenopausal women; however, FSH was significantly correlated with bone resorption (C-terminal collagen I cross-link) in perimenopausal women (age, 45-54 yr). Using multivariate analyses, serum InhA better predicted bone formation and resorption markers in premenopausal women than either FSH or bioavailable E2.

CONCLUSIONS

Decreases in inhibin levels across the menopause transition are associated with increasing bone turnover, regardless of changes in sex steroids or FSH.

OBJECTIVE

To determine that anti-Müllerian hormone (AMH) has been shown to inhibits E(2) production in rodents and in luteinized granulosa cells (GC). We determined whether this occurs in human cells most highly expressing AMH (i.e., from small antral follicles) and whether this is an effect on aromatase promoter activity. We also investigated the effects of AMH on other factors determining FSH sensitivity.

METHODS

Granulosa cells were exposed to AMH with and without gonadotropins for 48 hours.

METHODS

University laboratory.

METHODS

Not applicable.

METHODS

None.

METHODS

Aromatase and FSH receptor messenger RNA expression measured using real time quantitative polymerase chain reaction (PCR). Aromatase promoter II activity measured using a luciferase assay. Estradiol, inhibin A and B, and vascular endothelial growth factor production were measured in the conditioned medium.

RESULTS

The AMH decreased gonadotropin-stimulated aromatase expression and decreased forskolin-stimulated aromatase in KGN cells and this effect was through a dose-dependent inhibition of promoter II. Surprisingly, AMH also reduced FSH receptor mRNA expression. High AMH doses had no effect on inhibin B, whereas a low dose stimulated production. There was no effect on inhibin A or vascular endothelial growth factor.

CONCLUSIONS

The AMH inhibits factors affecting FSH sensitivity. As AMH levels decrease with follicle growth, this inhibition would be removed. The AMH overproduction in anovulatory polycystic ovaries (PCO) may therefore restrict folliculogenesis by an inhibitory effect on FSH sensitivity, thereby contributing to anovulation.