Regulation of the human menstrual cycle

Fertility conservation in breast cancer patients

Breast cancer is the most common malignant tumor in women. Increasing survival rates after breast cancer, new reproductive techniques and growing interest regarding the quality of life after cancer have brought the possibilities of fertility-preserving treatment to the center of attention of oncologists and affected patients. Many of these women suffer from infertility and premature menopause as a result of chemotherapy. Several measures, for example gonadotropin-releasing hormone analogs, hormonal stimulation to cryopreserve oocytes, ovarian tissue cryoconservation or a combination of the methods, can be undertaken depending on the hormone receptor status of the tumor, and the patient's age and partner status. Embryo cryopreservation is currently the most promising fertility preservation option. Early counseling on fertility-preserving strategies is of utmost importance, so that the fertility-preserving method can be integrated into the oncologic therapy regime.

Progesterone improves cognitive performance and attenuates smoking urges in abstinent smokers

BACKGROUND

Progesterone, a steroid hormone, has been implicated in many CNS functions including reward, cognition, and neuroprotection. The goal of this study was to examine the dose-dependent effects of progesterone on cognitive performance, smoking urges, and smoking behavior in smokers.

METHODS

Thirty female and thirty-four male smokers participated in a double-blind, placebo-controlled study. Female smokers were in the early follicular phase of their menstrual cycle during study participation. Smokers were randomly assigned to either 200 or 400mg/day of progesterone or placebo, given in two separate doses, during clinic visit. The first 3 days of the treatment period, smokers abstained from smoking, which was verified with breath CO levels. Smokers attended an experimental session on day 4 where the number of cigarettes smoked were recorded starting 2h after the medication treatment.

RESULTS

Progesterone treatment, 200mg/day, significantly improved cognitive performance in the Stroop and the Digit Symbol Substitution Test. Progesterone at 400mg/day was associated with reduced urges for smoking but did not change ad lib smoking behavior.

CONCLUSIONS

These findings suggest a potential therapeutic value of progesterone for smoking cessation.

Role of progesterone in nicotine addiction: evidence from initiation to relapse

Nicotine addiction continues to be the main cause of preventable death in developed countries. Women and teen girls appear to be more vulnerable on certain aspects of nicotine addiction compared with men and boys. While the mechanism of gender differences in nicotine addiction is not yet clear, evidence suggests that while estrogen may underlie enhanced vulnerability in females, progesterone may protect females. Thus, progesterone may have therapeutic use for tobacco addiction, especially in female smokers. A greater understanding of the role of progesterone in nicotine addiction is important not only from a treatment standpoint, but also from a prevention standpoint: hormone transition phases, such as those that occur at adolescence, and during pregnancy and following birth, as well as following hormonal manipulation (e.g., using methods of hormonal birth control), may all contribute to changes in vulnerability to nicotine addiction. In this review, we summarize recent evidence from clinical and preclinical studies examining the role of progesterone in nicotine addiction focusing on its role during initiation of use and during later phases of the addiction process as a potential relapse prevention treatment. We conclude with future directions including further examination of progesterone as a potential intervention and treatment of nicotine addiction.

From Fertilisation to Implantation in Mammalian Pregnancy-Modulation of Early Human Reproduction by the Endocannabinoid System

There is an increasing recognition that the endocannabinoid system is the crucial cytokine-hormone system regulating early human pregnancy. The synchronous development of the fertilized embryo and the endometrium to ensure timely implantation has been shown to be one of the pivotal steps to successful implantation. This development is thought to be regulated by a finely balanced relationship between various components of the endocannabinoid system in the endometrium, the embryo and the Fallopian tube. In addition, this system has also been shown to be involved in the regulation of the development and maturation of the gametes prior to fertilization. In this review, we will examine the evidence from animal and human studies to support the role of the endocannabinoid system in gametogenesis, fertilization, implantation, early pregnancy maintenance, and in immunomodulation of pregnancy. We will discuss the role of the cannabinoid receptors and the enzymes involved in the synthesis and degradation of the key endocannabinoid ligands (e.g., anandamide and 2-arachinoylglycerol) in early reproduction.

Investigating the impact of sex and cortisol on implicit fear conditioning with fMRI

Fear conditioning is influenced by stress but opposing effects in males and females have often been reported. In a previous human functional magnetic resonance imaging (fMRI) study, we observed acute effects of the stress hormone cortisol on prefrontal structures. Men showed evidence for impaired fear conditioning after cortisol treatment, while the opposite pattern was found for women. In the current experiment, we tested whether similar sex-dependent effects would occur on the neural level if contingency awareness was prevented experimentally to investigate implicit learning processes. A differential fear conditioning experiment with transcutaneous electrical stimulation as unconditioned stimulus and geometric figures as conditioned stimuli (CS) was conducted. One figure was always paired (CS+), whereas the other (CS-) was never paired with the UCS. Thirty-nine (19 female) subjects participated in this fMRI study, receiving either placebo or 30 mg cortisol (hydrocortisone) before conditioning. Dependent variables were skin conductance responses (SCRs) and neural activity (BOLD signal). In line with prior findings in unaware participants, no differential learning could be observed for the SCRs. However, a sex x cortisol interaction was detected with a reduced mean response to the CS after cortisol treatment in men, while the opposite pattern was observed in women (enhanced mean SCR under cortisol). In the contrast CS+ minus CS-, neural activity showed a sex x cortisol interaction in the insula and further trends in the hippocampus and the thalamus. In these regions, cortisol reduced the CS+/CS- differentiation in men but enhanced it in women. In contrast to these sex specific effects, differential amygdala activation was found in the placebo group but not in the cortisol group, irrespective of sex. Further, differential neural activity in the amygdala and thalamus were positively correlated with the SCRs in the placebo group only. The present study in contingency unaware participants illustrates that cortisol has in some brain regions sex specific effects on neural correlates of emotional learning. These effects might translate into a different vulnerability of the two sexes for anxiety disorders.

Progesterone effects on subjective and physiological responses to intravenous nicotine in male and female smokers

OBJECTIVE

Previous studies suggest possible modulatory effects of progesterone on nicotine addiction. The goal of this study was to determine the effects of progesterone, on acute physiological and subjective responses to intravenous (IV) nicotine in overnight abstinent male and female smokers.

METHODS

Twelve smokers, six males and six females, participated in a double-blind, placebo-controlled, crossover study, which consisted of two experimental sessions. Before each session, subjects were treated orally with a single dose of either 200 mg progesterone or placebo. Starting 2 h following the medication treatment, subjects received an IV saline injection, followed by 0.5 and 1.0 mg/70 kg IV nicotine.

RESULTS

Progesterone treatment, compared to placebo, enhanced the ratings of "bad effects," from IV nicotine and attenuated the rating of "drug liking." Progesterone also enhanced suppression of smoking urges by nicotine as assessed by the Brief Questionnaire on Smoking Urges (BQSU).

CONCLUSIONS

These results suggest that progesterone may alter the subjective effects of nicotine as well as urges to smoke cigarettes. Further studies are warranted to examine the modulation of nicotine's effects by gonadal hormones.

Sex hormones and mucosal wound healing

Wound healing studies, which have chiefly examined dermal tissues, have reported a female advantage in healing rates. In contrast, our laboratory recently demonstrated women heal mucosal wounds more slowly than men. We hypothesized sex hormones influence wound healing rates, possibly through their modulating effects on inflammation. This study involved 329 younger subjects aged 18-43 (165 women, 164 men) and 93 older subjects aged 50-88 (60 women, 33 men). A 3.5mm diameter wound was created on the hard oral palate and videographed daily to assess wound closure. Blood collected at the time of wounding was used to assess circulating testosterone, progesterone and estradiol levels, and in vitro cytokine production in response to LPS. No strong associations were observed between healing times and estradiol or progesterone levels. However, in younger subjects, lower testosterone levels related to faster wound closure. Conversely, in older women higher testosterone levels related to (1) lower inflammatory responses; and (2) faster healing times. No such relationships were seen in older men, or in women taking oral contraceptives or hormone replacement therapy [HRT]. Older women (50-54 years) not yet experiencing menopause healed similarly to younger women and dissimilarly from age-matched post-menopausal women. This suggests that the deleterious effects of aging on wound healing occur secondary to the effects of menopause. Supporting this, there was evidence in post-menopausal women that HRT augmented wound closure. Overall, this study suggests that human mucosal healing rates are modulated by testosterone levels. Based upon when between-group differences were observed, testosterone may impact upon the proliferative phase of healing which involves immune processes such as re-epithelialization and angiogenesis.

Differences in measured mammographic density in the menstrual cycle

BACKGROUND

In premenopausal women, the sensitivity of screening mammography for detecting breast cancer has been reported to be greater in the follicular phase than in the luteal phase of the menstrual cycle, which may be due to differences in mammographic density. To examine this possible effect, we compared mammographic density in premenopausal women who had mammograms at different phases of the menstrual cycle.

METHODS

We recruited premenopausal women ages 40 to 49 years from two mammography units in Toronto, recorded the first day of the last menstrual period (LMP) and measured mammographic density using Cumulus software. We classified the time of the mammography examination as having occurred in one of four intervals, 1 (first week after LMP), 2 (second week after LMP), 3 (third week after LMP) and 4 (>3 weeks after LMP), and compared mammographic density across intervals.

RESULTS

Of the 936 women included in the analysis, 620 were examined by film and 316 by digital mammography. There were small and statistically nonsignificant variations in breast dense, nondense area, and percent density over the menstrual cycle in women examined by film mammography. Marginally significant variation in percent density was observed in the digital subset due to significant differences in the amount of nondense tissue over the menstrual cycle.

CONCLUSION

Variations in mammographic density over the menstrual cycle were small and nonsignificant for women examined by either film or digital mammography. Thus, timing of mammography in menstrual cycle is unlikely to have a significant influence in breast cancer detection by screening mammography.

Can Drosophila melanogaster represent a model system for the detection of reproductive adverse drug reactions?

Once a molecule is identified as a potential drug, the detection of adverse drug reactions is one of the key components of its development and the FDA approval process. We propose using Drosophila melanogaster to screen for reproductive adverse drug reactions in the early stages of drug development. Compared with other non-mammalian models, D. melanogaster has many similarities to the mammalian reproductive system, including putative sex hormones and conserved proteins involved in genitourinary development. Furthermore, the D. melanogaster model would present significant advantages in time efficiency and cost-effectiveness compared with mammalian models. We present data on methotrexate (MTX) reproductive adverse events in multiple animal models, including fruit flies, as proof-of-concept for the use of the D. melanogaster model.

Simultaneous quantification of GABAergic 3alpha,5alpha/3alpha,5beta neuroactive steroids in human and rat serum

The 3alpha,5alpha- and 3alpha,5beta-reduced derivatives of progesterone, deoxycorticosterone, dehydroepiandrosterone and testosterone enhance GABAergic neurotransmission and produce inhibitory neurobehavioral and anti-inflammatory effects. Despite substantial information on the progesterone derivative (3alpha,5alpha)-3-hydroxypregnan-20-one (3alpha,5alpha-THP, allopregnanolone), the physiological significance of the other endogenous GABAergic neuroactive steroids has remained elusive. Here, we describe the validation of a method using gas chromatography-mass spectrometry to simultaneously identify serum levels of the eight 3alpha,5alpha- and 3alpha,5beta-reduced derivatives of progesterone, deoxycorticosterone, dehydroepiandrosterone and testosterone. The method shows specificity, sensitivity and enhanced throughput compared to other methods already available for neuroactive steroid quantification. Administration of pregnenolone to rats and progesterone to women produced selective effects on the 3alpha,5alpha- and 3alpha,5beta-reduced neuroactive steroids, indicating differential regulation of their biosynthetic pathways. Pregnenolone administration increased serum levels of 3alpha,5alpha-THP (+1488%, p<0.001), (3alpha,5alpha)-3,21-dihydroxypregnan-20-one (3alpha,5alpha-THDOC, +205%, p<0.01), (3alpha,5alpha)-3-hydroxyandrostan-17-one (3alpha,5alpha-A, +216%, p<0.001), (3alpha,5alpha,17beta)-androstane-3,17-diol (3alpha,5alpha-A-diol, +190%, p<0.01). (3alpha,5beta)-3-hydroxypregnan-20-one (3alpha,5beta-THP) and (3alpha,5beta)-3-hydroxyandrostan-17-one (3alpha,5beta-A) were not altered, while (3alpha,5beta)-3,21-dihydroxypregnan-20-one (3alpha,5beta-THDOC) and (3alpha,5beta,17beta)-androstane-3,17-diol (3alpha,5beta-A-diol) were increased from undetectable levels to 271+/-100 and 2.4+/-0.9 pg+/-SEM, respectively (5/8 rats). Progesterone administration increased serum levels of 3alpha,5alpha-THP (+1806%, p<0.0001), 3alpha,5beta-THP (+575%, p<0.001), 3alpha,5alpha-THDOC (+309%, p<0.001). 3alpha,5beta-THDOC levels were increased by 307%, although this increase was not significant because this steroid was detected only in 3/16 control subjects. Levels of 3alpha,5alpha-A, 3alpha,5beta-A and pregnenolone were not altered. This method can be used to investigate the physiological and pathological role of neuroactive steroids and to develop biomarkers and new therapeutics for neurological and psychiatric disorders.

Effect of menopause on the chemical control of breathing and its relationship with acid-base status

This study examined the role of alterations in the chemoreflex control of breathing, acid-base balance, and their interaction in postmenopausal ventilatory adaptations. A modified iso-oxic hyperoxic and hypoxic CO(2)-rebreathing procedure was employed to evaluate central and peripheral chemoreflex drives to breathe, respectively, in 15 healthy postmenopausal and 20 premenopausal women of similar age. Arterialized venous blood samples were collected at rest for the estimation of arterial Pco(2) (Pa(CO(2))) and H(+) concentration ([H(+)]), plasma strong ion difference ([SID]) and total weak acid ([A](tot)) concentrations, and serum progesterone ([P(4)]) and 17beta-estradiol ([E(2)]) concentrations. In post- compared with premenopausal women, Pa(CO(2)), [SID], and the central chemoreflex ventilatory recruitment threshold for Pco(2) (VRTco(2)) were higher, whereas [P(4)] and [E(2)] were lower (all P < 0.05), with no significant change in central or peripheral chemoreflex sensitivity, peripheral chemoreflex VRTco(2), and [A](tot). The acidifying effect of an increased Pa(CO(2)) was offset by the alkalizing effect of an increased [SID], such that [H(+)] was preserved in post- compared with premenopausal women. Pa(CO(2)) correlated positively with the central chemoreflex VRTco(2) (r = 0.67, P < 0.01), which in turn correlated positively with [SID] (r = 0.53, P < 0.01) within the pooled data. In conclusion, the relative alveolar hypoventilation and attendant arterial hypercapnia in healthy post- compared with premenopausal women could be explained, in part, by the interaction of 1) reduced central, but not peripheral, chemoreflex VRTco(2), 2) increased [SID], and 3) reduced circulating female sex steroid hormone concentrations.

The Macaque Endometrium, with Special Reference to the Cynomolgus Monkey (Macaca fascicularis)

The macaque endometrium undergoes dramatic morphologic and functional changes during the menstrual cycle that are nearly identical to those of the human endometrium. The sequential events that take place in the endometrium are mainly driven by the ovarian steroids and their respective receptors. To be able to interpret the changes and effects induced by mammalian or synthetic hormones and other compounds that could have influence on the hormonal status of the animal, a thorough knowledge of the anatomy, physiology, and histology of the cyclic hormone-mediated processes within the endometrium is indispensable. In this paper we give an overview of uterine growth and development, anatomy, basic histology, aging, spontaneous pathology, and the techniques to study the endometrium in-life. In addtion, a comprehensive description of the receptor-mediated, hormone-driven morphological changes during the menstrual cycle in the cynomolgus monkey (Macaca fascicularis) is given. Where possible, differences between the macaque and human endometria are discussed.

Competing Interests: This article was sponsored by Covance Inc. and Schering-Plough. Gerhard F. Weinbauer and Eberhard Buse are employed by Covance Inc. Eric Van Esch is employed by Schering-Plough. No other competing interests were declared.

Reproductive hormones in plasma over the menstrual cycle in primary dysmenorrhea compared with healthy subjects

The pathogenesis of primary dysmenorrhea is still poorly understood. The objective of the present investigation was to study differences in plasma concentrations of reproductive hormones in women with primary dysmenorrhea vs. healthy controls. In a prospective, parallel-group study we determined the plasma concentrations of oxytocin, vasopressin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17beta-estradiol (17beta-E2), progesterone and prostaglandin F 2alpha metabolite (15-keto-13,14-dihydro-PGF 2alpha) over one menstrual cycle in eight women with primary dysmenorrhea and eight healthy volunteers. In dysmenorrheic women the plasma concentration of oxytocin was significantly higher at menstruation (p = 0.0084) and that of vasopressin significantly lower at ovulation (p = 0.0281) compared with healthy women. They had also higher FSH levels in the early follicular phase (p = 0.0087) and at menstruation (p = 0.0066) and the 17beta-E2 concentration was higher in the late follicular phase (p = 0.0449). No differences were seen for LH, progesterone and PGF 2alpha metabolite. The differences of oxytocin, vasopressin, FSH and 17beta-E2 concentrations found in plasma suggest an involvement of these hormones in mechanisms of primary dysmenorrhea. These mechanisms seem to be mainly regulated through the hypothalamus and pituitary. The influence of oxytocin on the non-pregnant uterus seems to be more important than earlier believed.

Does meloxicam increase the incidence of anovulation induced by single administration of levonorgestrel in emergency contraception? A pilot study

BACKGROUND

Levonorgestrel (LNG) consistently prevents follicular rupture only when it is given before the onset of the ovulatory stimulus. As locally synthesized prostaglandin (PG) plays a crucial role in follicular rupture and cyclooxygenase-2 (cox-2) catalyses the final step of PG synthesis, we reasoned that adding a cox-2 inhibitor to LNG would prevent follicular rupture even after the ovulatory process had been triggered by the gonadotrophin surge.

METHODS

Forty-one women were divided into two groups. One was treated when the size of the leading follicle was 15-17 mm (n=10) and the other when it was >or=18 mm (n=31). Each woman contributed with one cycle treated with LNG 1.5 mg single dose plus placebo and another treated with LNG + meloxicam (Melox) 15 mg, in a randomized order. Serial blood sampling for the assay of LH and follicular monitoring by transvaginal ultrasound were performed before and after treatment.

RESULTS

Follicular rupture failed to occur within the 5-day period that followed treatment in 50 and 70% of cycles treated with LNG + Placebo and LNG + Melox, respectively, in the 15-17 mm group (P=0.15) and in 16 and 39% of cycles treated with LNG + Placebo and LNG + Melox, respectively, in the >or=18 mm group (P < 0.052). The overall proportion of cycles with no follicular rupture or ovulatory dysfunction increased significantly by the addition of Melox to LNG (66 versus 88%, P < 0.012; n=41-matched pairs).

CONCLUSIONS

The trend towards increased incidence of no follicular rupture when Melox was combined with LNG suggests that the addition of a cox-2 inhibitor has the potential to improve the contraceptive efficacy of LNG by a pre-fertilization effect.

Inhibition of proliferation of endometrial stromal cells by trichostatin A, RU486, CDB-2914, N-acetylcysteine, and ICI 182780

BACKGROUND

All current major medications in treating endometriosis are effective in treating pain, most likely through suppression of proliferation of the implants, yet their effectiveness is relatively short term and they all have many undesirable, and sometimes severe, side effects. There is pressing need for novel, more effective medications in treating endometriosis with less and/or milder side effects.

METHODS

Using a recently established immortalized endometrial stromal cell line, we carried out cell proliferation assays for cells treated with trichostatin A (TSA), RU486, CDB-2914, and N-acetylcysteine, and ICI 182780. Gene expression levels for PR-A, PR-B, AR, Fas and FasL were measured. Protein expression levels for ERalpha, ERbeta, and AR were also measured.

RESULTS

Cell proliferation assay results for NAC, H2O2, CDB, and RU486 were nearly identical or similar to what have been reported based on primary cell cultures or in vivo studies. TSA, CDB, RU486 and NAC all had various antiproliferative effects. TSA had a more potent and longer lasting antiproliferative effect than CDB and NAC, even in the presence of an oxidant, H2O2. Its antiproliferative effect was concentration-dependent. ICI did not have a significant antiproliferative effect. PR-A, PR-B, AR, and FasL expression were all increased as compared with untreated cells.

CONCLUSIONS

The cell line appears to be an adequate model for stromal components of endometriotic implants. That ICI has no inhibitory effect on endometrial proliferation may explain why a phase II clinical trial on its use to treat endometriosis did not advance to later stages. The upregulation of PR-B and AR may be responsible for antiproliferative effects induced by TSA, a histone deacetylase inhibitor (HDACI). HDACIs may be promising therapeutics in treating endometriosis due to their antiproliferative effects as well as the potential to restore gene dysregulation through chromatin remodeling.

Phasic menstrual cycle effects on the control of breathing in healthy women

This study examined the effects of menstrual cycle phase on ventilatory control. Fourteen eumenorrheic women were studied in the early follicular (FP; 1-6 days) and mid-luteal (LP; 20-24 days) phase of the menstrual cycle. Blood for the determination of arterial PCO(2) (PaCO(2)) , plasma strong ion difference ([SID]), progesterone ([P(4)]), and 17beta-estradiol ([E(2)]) concentrations were obtained at rest. Subjects performed a CO(2) rebreathing procedure that included prior hyperventilation and maintenance of iso-oxia to evaluate central and peripheral chemoreflex, and nonchemoreflex drives to breathe. Resting PaCO(2) and [SID] were lower; minute ventilation (V (E)), [P(4)] and [E(2)] were higher in the LP versus FP. Within the LP, significant correlations were observed for PaCO(2) with [P(4)], [E(2)] and [SID]. Menstrual cycle phase had no effect on the threshold or sensitivity of the central and/or peripheral ventilatory chemoreflex response to CO(2). Both (V (E)) and the ventilatory response to hypocapnia (representing nonchemoreflex drives to breathe) were approximately 1L/min greater in the LP versus FP accounting for the reduction in PaCO(2) . These data support the hypothesis that phasic menstrual cycle changes in PaCO(2) may be due, at least in part, to the stimulatory effects of [P(4)], [E(2)] and [SID] on ventilatory drive.

Putative stem cell activity of human endometrial epithelial and stromal cells during the menstrual cycle

OBJECTIVE

To determine whether menstrual cycle stage or activity has an effect on the clonogenic activity of human endometrial epithelial and stromal cells.

DESIGN

Clonal analysis of human endometrial epithelial and stromal cells derived from full-thickness endometrium.

SETTING

University research laboratory.

PATIENT(S)

Twenty-six women of varying age and race undergoing hysterectomy for nonendometrial pathologies.

INTERVENTION(S)

Full-thickness human endometrial tissue was dissociated into single cells. Epithelial and stromal cells were separated using magnetic beads, and cloning assays were performed in serum-containing or growth factor-supplemented serum-free medium.

MAIN OUTCOME MEASURE(S)

Clonogenic activity of epithelial and stromal cells.

RESULT(S)

Clonogenicity of epithelial and stromal cells did not vary significantly between proliferative, secretory, and inactive endometrium. However, epithelial and stromal cells did show a trend for greater numbers of clonogenic cells in secretory and proliferative endometrium respectively. A large variation between samples was observed, which may have masked any significant differences.

CONCLUSION(S)

We found that clonogenicity does not vary from the proliferative to secretory stage of the menstrual cycle, or between active, cycling and inactive endometrium for both epithelial and stromal cells. We have demonstrated for the first time that inactive endometrium contains clonogenic epithelial and stromal cells.

Inhibition of Stat3 activation in the endometrium prevents implantation: a nonsteroidal approach to contraception

Activation of the receptors for leukemia inhibitory factor (LIF) and IL-11 is essential for embryo attachment and decidualization in mice. Both receptors induce activation of the Stat family of signal transducers via the Jak/Stat pathway. Here, we aimed to establish whether activation of Stat3 in maternal endometrium is essential for successful implantation. Functional blockade of Stat3 before implantation, by injection into the uterine lumen of a cell-permeable Stat3 peptide inhibitor, reduced embryo implantation specifically by 70% (P < 0.001). Stat3 is phosphorylated in the luminal epithelium (LE) in response to LIF, and this phosphorylation was significantly reduced both in vitro and in vivo by the Stat3 inhibitor. The inhibitor also blocked induction by LIF of several LIF-regulated genes in the LE including Irg1, which has been shown previously to be essential for implantation. Successful implantation is therefore dependent on phosphorylation and activation of Stat3 in the endometrium before implantation. This finding provides a target for contraceptive development, based on selective blockade of signal transduction pathways essential for implantation. This study demonstrates that cell-permeable peptide inhibitors can be used effectively to target intracellular signaling pathways in the uterine LE.

Strategies and methods for research on sex differences in brain and behavior

Female and male brains differ. Differences begin early during development due to a combination of genetic and hormonal events and continue throughout the lifespan of an individual. Although researchers from a myriad of disciplines are beginning to appreciate the importance of considering sex differences in the design and interpretation of their studies, this is an area that is full of potential pitfalls. A female's reproductive status and ovarian cycle have to be taken into account when studying sex differences in health and disease susceptibility, in the pharmacological effects of drugs, and in the study of brain and behavior. To investigate sex differences in brain and behavior there is a logical series of questions that should be answered in a comprehensive investigation of any trait. First, it is important to determine that there is a sex difference in the trait in intact males and females, taking into consideration the reproductive cycle of the female. Then, one must consider whether the sex difference is attributable to the actions of gonadal steroids at the time of testing and/or is sexually differentiated permanently by the action of gonadal steroids during development. To answer these questions requires knowledge of how to assess and/or manipulate the hormonal condition of the subjects in the experiment appropriately. This article describes methods and procedures to assist scientists new to the field in designing and conducting experiments to investigate sex differences in research involving both laboratory animals and humans.

Women's sleep in health and disease

A huge amount of knowledge about sleep has accumulated during the last 5 decades following the discovery of rapid eye movement (REM) sleep. Nevertheless, there are numerous areas of considerable ignorance. One of these concerns the particularities of sleep in women. Most basic and clinical studies have been performed in male subjects, and only very recently research groups around the world have addressed women's sleep in health and disease. In this review, we summarize the present knowledge on the influence of oestrogens on the brain and on the distinctive changes of sleep across the menstrual cycle, during pregnancy and menopause. In addition, studies in female rodents are reviewed as well as the knowledge on female peculiarities regarding the interactions between sleep regulation and age-related changes in circadian rhythms. We also address specific aspects of sleep loss and sleep disorders in women. Finally, very recent studies on the sociology of sleep are summarized and future directions in the field are discussed.

Inhibin/activin subunits alpha, beta-A and beta-B are differentially expressed in normal human endometrium throughout the menstrual cycle

Inhibins are dimeric glycoproteins composed of an alpha (alpha) subunit and one of two possible beta (beta-) subunits (betaA or betaB). The aims of this study were to assess the frequency and tissue distribution patterns of the inhibin subunits in normal human endometrium. Samples from human endometrium from proliferative phase (PP; n=32), early secretory phase (ES; n=10) and late secretory phase (LS; n=12) were obtained. Immunohistochemistry, immunofluorescence and a statistical analysis were performed. All three inhibin subunits were expressed by normal endometrium by immunohistochemistry and immunofluorescence. Inhibin-alpha was primarily detected in glandular epithelial cells, while inhibin-beta subunits were additionally localised in stromal tissue. Inhibin-alpha staining reaction increased significantly between PP and ES (P<0.05), PP and LS (P<0.01), and ES and LS (P<0.02). Inhibin-betaA and -betaB were significant higher in LS than PP (P<0.05) and LS than ES (P<0.05). All three inhibin subunits were expressed by human endometrium varying across the menstrual cycle. This suggests substantial functions in human implantation of inhibin-alpha subunit, while stromal expression of the beta subunits could be important in the paracrine signalling for adequate endometrial maturation. The distinct expression in human endometrial tissue suggests a synthesis of inhibins into the lumen and a predominant secretion of activins into the stroma.

Expression of the inhibin-alpha subunit in normal, hyperplastic and malignant endometrial tissue: an immunohistochemical analysis

OBJECTIVES

Determination of the frequency and tissue distribution of inhibin-alpha (INH-alpha) in normal, hyperplastic and malignant endometrium.

MATERIALS AND METHODS

Endometrial tissue was obtained from normal, hyperplastic (glandular-cystic hyperplasia), adenomatous hyperplasia (AH grade I to III) and endometroid adenocarcinoma and immunohistochemically characterized with INH-alpha antibody.

RESULTS

INH-alpha was expressed in normal, hyperplastic and malignant endometrium. Highest expression was observed during secretory phase and glandular-cystic hyperplasia compared to all groups. A continuous decline was noted from AH grade I to III with a significance between AH I and II.

DISCUSSION

A menstrual cycle associated expression of INH-alpha in glandular endometrial epithelium was observed. Since AH grade II and III can be considered as a precursor of endometrial cancer, INH-alpha could be a marker of cell transformation and an endometrial tumor-suppressor agent.

Oral contraception and cyclic changes in premenstrual and menstrual experiences

Despite the widespread use of oral contraceptives (OC) there is no consensus regarding their effect on menstrual cycle experiences. This study examines the cyclic changes of prospectively collected, daily menstrual cycle experiences of two groups of 'healthy women' using monophasic and triphasic OC compared with a group using non-hormonal contraception. A total of 119 'healthy women' using monophasic, triphasic or non-hormonal contraception for three months, made daily ratings over at least two complete menstrual cycles. Cyclic changes of ratings within and between the groups were analyzed. The three groups showed significant cyclic changes in abdominal fullness, abdominal discomfort, breast fullness, general 'premenstrual syndrome-like symptoms' and in at least two mood ratings. Maximal changes in ratings occurred during the late premenstrual and menstrual phases. There were no significant differences between the three groups in cyclic changes for any physical rating, but there were for tiredness or fatigue (non-OC users reported experiencing tiredness or fatigue more frequently than the OC users) and sadness or depression (non-OC users experienced sadness or depression less frequently than OC users during the early part of the cycle, followed by a sharp rise from early premenstrual to the menstrual phase). There were no significant cyclic differences in ratings between the monophasic and triphasic groups. In conclusion, 'healthy women' using OC experience premenstrual and menstrual changes. Any differences between OC formulations are subtle and not of clinical significance in 'healthy women' already established on monophasic or triphasic hormonal contraception.

Partnership status and the temporal context of relationships influence human female preferences for sexual dimorphism in male face shape

Secondary sexual characteristics may indicate quality of the immune system and therefore a preference for masculinity may confer genetic benefits to offspring; however, high masculinity may be associated with costs of decreased paternal investment. The current study examined women's preferences for masculinity in male faces by using computer graphics to allow transformation between feminine and masculine versions of individual male faces. We found that preferences for masculinity are increased when women either have a partner or are considering a short-term relationship. Such preferences are potentially adaptive, serving to: (i) maximize parental investment and cooperation in long-term relationships by biasing choices towards feminine faced males, and (ii) maximize possible good-gene benefits of short-term or extra-pair partners by biasing choices towards masculine faced males. We also found that individuals using oral contraception do not show the above effects, indicating that such hormonal intervention potentially disrupts women's choices for evolutionarily relevant benefits from males.

Changes of ovarian interstitial cell hormone receptors and behavior of resident mesenchymal cells in developing and adult rats with steroid-induced sterility

In the present paper, we report that injection of testosterone propionate (500 microg) during the critical window of rat development (postnatal day 5) induces temporary appearance of aged interstitial cells in developing ovaries (days 7 and 10). Aged interstitial cells showed large size (> or = 12 microm), enhanced androgen receptor (AR) and low estrogen (ER) and luteinizing hormone receptor (LHR) expression. Although normal mature interstitial cells (large size and strong ER and LHR expression) appeared later (day 14), and ovaries of androgenized rats were similar to normal ovaries between days 14 and 35, ovaries of adult androgenized females showed only aged and no mature interstitial cells. Androgenization on day 10 caused the development of aged interstitial cells on day 14, but adult ovaries were normal. Long lasting postnatal estrogenization (estradiol dipropionate for four postnatal weeks) caused in developing and adult ovaries a lack of interstitial cell development beyond the immature state. Immature interstitial cells were characterized by a small size (< or = 7 microm) and a lack of AR, ER and LHR expression. Because the critical window for steroid-induced sterility coincides with the termination of immune adaptation, we also investigated distribution of mesenchymal cells (Thy-1 mast cells and pericytes, ED1 monocyte-derived cells, CD8 T cells, and cells expressing OX-62 of dendritic cells) in developing and adult ovaries. Developing ovaries of normal, androgenized and estrogenized females were populated by similar mesenchymal cells, regardless of differences in the state of differentiation of interstitial cells. However, mesenchymal cells in adult ovaries showed distinct behavior. In normal adult ovaries, differentiation of mature interstitial cells was accompanied by differentiation of mesenchymal cells. Aged interstitial cells in ovaries of androgenized rats showed precipitous degeneration of resident mesenchymal cells. Immature interstitial cells in ovaries of estrogenized rats showed a lack of differentiation of resident mesenchymal cells. These observations indicate that an alteration of interstitial cell differentiation during immune adaptation toward the aged phenotype results in precipitous degeneration of resident mesenchymal cells and premature aging of ovaries in adult rats, and alteration toward immature phenotype results in a lack of differentiation of mesenchymal cells and permanent immaturity of ovaries in adult females.

Cellular turnover in the mammary gland is correlated with systemic levels of progesterone and not 17beta-estradiol during the estrous cycle

Adult mammary tissue has been considered "resting" with minimal morphological change. Here, we reveal the dynamic nature of the nulliparous murine mammary gland. We demonstrate specific changes at the morphological and cellular levels, and uncover their relationship with the murine estrous cycle and physiological levels of steroid hormones. Differences in the numbers of higher-order epithelial branches and alveolar development led to extensive mouse-to-mouse mammary variations. Morphology (assigned grades 0-3) ranged from a complete lack of alveoli to the presence of numerous alveoli emanating from branches. Morphological changes were driven by epithelial proliferation and apoptosis, which differed between ductal versus alveolar structures. Proliferation within alveolar epithelium increased as morphological grade increased. Extensive alveolar apoptosis was restricted to tissue exhibiting grade 3 morphology, and was approximately 14-fold higher than at all other grades. Epithelial proliferation and apoptosis exhibited a positive relationship with serum levels of progesterone, but not with 17beta-estradiol. Compared with other estrous stages, diestrus was unique in that the morphological grade, epithelial proliferation, apoptosis, and progesterone levels all peaked at this stage. The regulated tissue remodeling of the mammary gland was orchestrated with mRNA changes in specific matrix metalloproteinases (MMP-9 and MMP-13) and specific tissue inhibitors of metalloproteinases (TIMP-3 and TIMP-4). We propose that the cyclical turnover of epithelial cells within the adult mammary tissue is a sum of spatial and functional coordination of hormonal and matrix regulatory factors.

Biological timing and the clock metaphor: oscillatory and hourglass mechanisms

Living organisms have developed a multitude of timing mechanisms--"biological clocks." Their mechanisms are based on either oscillations (oscillatory clocks) or unidirectional processes (hourglass clocks). Oscillatory clocks comprise circatidal, circalunidian, circadian, circalunar, and circannual oscillations--which keep time with environmental periodicities--as well as ultradian oscillations, ovarian cycles, and oscillations in development and in the brain, which keep time with biological timescales. These clocks mainly determine time points at specific phases of their oscillations. Hourglass clocks are predominantly found in development and aging and also in the brain. They determine time intervals (duration). More complex timing systems combine oscillatory and hourglass mechanisms, such as the case for cell cycle, sleep initiation, or brain clocks, whereas others combine external and internal periodicities (photoperiodism, seasonal reproduction). A definition of a biological clock may be derived from its control of functions external to its own processes and its use in determining temporal order (sequences of events) or durations. Biological and chemical oscillators are characterized by positive and negative feedback (or feedforward) mechanisms. During evolution, living organisms made use of the many existing oscillations for signal transmission, movement, and pump mechanisms, as well as for clocks. Some clocks, such as the circadian clock, that time with environmental periodicities are usually compensated (stabilized) against temperature, whereas other clocks, such as the cell cycle, that keep time with an organismic timescale are not compensated. This difference may be related to the predominance of negative feedback in the first class of clocks and a predominance of positive feedback (autocatalytic amplification) in the second class. The present knowledge of a compensated clock (the circadian oscillator) and an uncompensated clock (the cell cycle), as well as relevant models, are briefly re viewed. Hourglass clocks are based on linear or exponential unidirectional processes that trigger events mainly in the course of development and aging. An important hourglass mechanism within the aging process is the limitation of cell division capacity by the length of telomeres. The mechanism of this clock is briefly reviewed. In all clock mechanisms, thresholds at which "dependent variables" are triggered play an important role.

Angiogenesis and vascular regression in the ovary

Angiogenesis is prominent during development and downregulated in the adult. Strictly controlled angiogenesis in the healthy adult occurs cyclically in the ovary and corpus luteum, which therefore make an excellent model with which to study vascular growth. Dysfunctional or uncontrolled angiogenesis is involved in a number of diseases and is responsible for growth and dissemination of tumours. This review focuses on the following aspects of the ovary: the gross and microscopical anatomy of the blood vessels, described mainly--but not exclusively--in the bovine; vascularization of the follicle before and after ovulation; angiogenesis in the developing and the mature corpus luteum as well as in the corpus luteum of pregnancy. The potential mechanisms of vascular regression during luteolysis and the potential role of vascular growth in dominance and atresia of follicles will be described. Furthermore, recent research on ovarian angiogenic and potential anti-angiogenic factors including fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF), angiopoietin and metalloproteinase inhibitor will be presented. Finally, the role of hormones including FSH, LH, sexual steroids, prostaglandins, prolactin, oxytocin and activin/inhibin in ovarian angiogenesis will be summarized. Future research is likely to yield valuable information that can contribute to the development of novel therapeutic strategies for the treatment of diseases characterized by disregulated angiogenesis and vascular regression.

Role of progesterone receptor activation in pituitary adenylate cyclase activating polypeptide gene expression in rat ovary

It is well known that the pituitary gonadotropin surge induces progesterone receptor (PR) gene expression in luteinizing granulosa cells and that PR activation is critical for successful ovulation. To further understand the molecular mechanism(s) by which PR plays a role critical for granulosa cell functions, we wanted to identify progesterone-induced genes in granulosa cells. We employed a PCR-based subtraction cloning strategy to screen for genes expressed differentially in granulosa cells that were challenged with forskolin in the presence of progesterone or ZK98299. One such differentially expressed clone was identified as the pituitary adenylate cyclase activating polypeptide (PACAP). To begin to understand the relationship between PR activation and PACAP gene expression in luteinizing granulosa cells, we examined whether PR and PACAP messenger RNA (mRNA) expression is temporally correlated. In cultured granulosa cells, both human CG and forskolin induced PR and PACAP mRNA levels in a dose-dependent manner, as determined by semi-quantitative RT-PCR assays. However, the peak expression for PR and PACAP mRNAs was observed at 3 h and 6 h after hormone treatment, respectively. This time difference in cAMP-responsive expression of the PR and PACAP genes is due, at least in part, to the requirement of ongoing protein synthesis for PACAP expression, as demonstrated by the inhibitory effect of cycloheximide on cAMP-induced PACAP, but not PR, mRNA levels. To determine whether PR synthesis is prerequisite for PACAP expression, we examined the effect of ZK98299, a specific PR antagonist, on cAMP-induced PACAP mRNA expression. This compound blocked cAMP-induced PACAP mRNA expression in a dose-dependent manner, indicating that PR activation is required for PACAP gene expression in granulosa cells. We then compared cellular localization and hormonal regulation of ovarian PR and PACAP gene expression in immature rats treated with gonadotropins as well as in adult rats during the preovulatory period by using in situ hybridization and semiquantitative RT-PCR assays. Results show that both PR and PACAP mRNAs are induced in granulosa cells of preovulatory follicles by human CG, but that the PR gene is expressed before the PACAP gene. Taken together, these results demonstrate that PRs mediate the LH-induced PACAP gene expression in rat granulosa cells.