Effect of menstrual cycle phase on carbohydrate supplementation during prolonged exercise to fatigue.

The effects of menstrual cycle phase and carbohydrate (CHO) supplementation were investigated during prolonged exercise. Nine healthy, moderately trained women cycled at 70% peak O(2) consumption until exhaustion. Two trials were completed during the follicular (Fol) and luteal (Lut) phases of the menstrual cycle. Subjects consumed 0.6 g CHO. kg body wt(-1). h(-1) (5 ml/kg of a 6% CHO solution every 30 min beginning at min 30 of exercise) or a placebo drink (Pl) during exercise. Time to exhaustion during CHO increased from Pl values (P < 0.05) by 14.4 +/- 8.5 (Fol) and 11.4 +/- 7.1% (Lut); no differences were observed between menstrual cycle phases. CHO attenuated (P < 0.05) the decrease in plasma glucose and insulin and the increase in plasma free fatty acids, tryptophan, epinephrine, and cortisol observed during Pl for both phases. Plasma alanine, glutamine, proline, and isoleucine were lower (P < 0.05) in Lut than in Fol phase. CHO resulted in lower (P < 0.05) plasma tyrosine, valine, leucine, isoleucine, and phenylalanine. These results indicate that the menstrual cycle phase does not alter the effects of CHO supplementation on performance and plasma levels of related substrates during prolonged exercise.     

Glucose kinetics and exercise performance during phases of the menstrual cycle: effect of glucose ingestion

To study the effect of menstrual cycle phase and carbohydrate ingestion on glucose kinetics and exercise performance, eight healthy, moderately trained, eumenorrheic women cycled at 70% of peak O(2) consumption for 2 h and then performed a 4 kJ/kg body wt time trial. A control (C) and a glucose ingestion (G) trial were completed during the follicular (F) and luteal (L) phases of the menstrual cycle. Plasma substrate concentrations were similar before the commencement of exercise. Glucose rates of appearance and disappearance were higher (P < 0.05) during the 2nd h of exercise in FC than in LC. The percent contribution of carbohydrate to total energy expenditure was greater in FC than in LC, and subjects performed better (13%, P < 0.05) in FC. Performance improved (19% and 26% in FG and LG compared with FC and LC, respectively, P < 0.05) with the ingestion of glucose throughout exercise. These data demonstrate that substrate metabolism and exercise performance are influenced by the menstrual cycle phase, but ingestion of glucose minimizes these effects.     

Vestibulosympathetic reflex during the early follicular and midluteal phases of the menstrual cycle

Evidence suggests that both the arterial baroreflex and vestibulosympathetic reflex contribute to blood pressure regulation, and both autonomic reflexes integrate centrally in the medulla cardiovascular center. A previous report indicated increased sympathetic baroreflex sensitivity during the midluteal (ML) phase of the menstrual cycle compared with the early follicular (EF) phase. On the basis of this finding, we hypothesize an augmented vestibulosympathetic reflex during the ML phase of the menstrual cycle. Muscle sympathetic nerve activity (MSNA), mean arterial pressure (MAP), and heart rate responses to head-down rotation (HDR) were measured in 10 healthy females during the EF and ML phases of the menstrual cycle. Plasma estradiol (Delta72 +/- 13 pg/ml, P < 0.01) and progesterone (Delta8 +/- 2 ng/ml, P < 0.01) were significantly greater during the ML phase compared with the EF phase. The menstrual cycle did not alter resting MSNA, MAP, and heart rate (EF: 13 +/- 3 bursts/min, 80 +/- 2 mmHg, 65 +/- 2 beats/min vs. ML: 14 +/- 3 bursts/min, 81 +/- 3 mmHg, 64 +/- 3 beats/min). During the EF phase, HDR increased MSNA (Delta3 +/- 1 bursts/min, P < 0.02) but did not change MAP or heart rate (Delta0 +/- 1 mmHg and Delta1 +/- 1 beats/min). During the ML phase, HDR increased both MSNA and MAP (Delta4 +/- 1 bursts/min and Delta3 +/- 1 mmHg, P < 0.04) with no change in heart rate (Delta0 +/- 1 beats/min). MSNA and heart rate responses to HDR were not different between the EF and ML phases, but MAP responses to HDR were augmented during the ML phase (P < 0.03). Our results demonstrate that the menstrual cycle does not influence the vestibulosympathetic reflex but appears to alter MAP responses to HDR during the ML phase.     

Expression of calbindin-D28k and its regulation by estrogen in the human endometrium during the menstrual cycle

Human endometrium resists embryo implantation except during the 'window of receptivity'. A change in endometrial gene expression is required for the development of receptivity. Uterine calbindin-D28k (CaBP-28k) is involved in the regulation of endometrial receptivity by intracellular Ca2+. Currently, this protein is known to be mainly expressed in brain, kidneys, and pancreas, but potential role(s) of CaBP-28k in the human uterus during the menstrual cycle remain to be clarified. Thus, in this study we demonstrated the expression of CaBP-28k in the human endometrium in distinct menstrual phases. During the human menstrual cycle, uterine expression levels of CaBP-28k mRNA and protein increased in the proliferative phase and fluctuated in these tissues, compared with that observed in other phases. We assessed the effects of two sex-steroid hormones, 17beta-estradiol (E2) and progesterone (P4), on the expression of CaBP-28k in Ishikawa cells. A significant increase in the expression of CaBP-28k mRNA was observed at the concentrations of E2 (10(-9 to -7) M). In addition, spatial expression of CaBP-28k protein was detected by immunohistochemistry. CaBP-28k was abundantly localized in the cytoplasm of the luminal and glandular epithelial cells during the proliferative phases (early-, mid-, late-) and early-secretory phase of menstrual cycle. Taken together, these results indicate that CaBP-28k, a uterine calcium binding protein, is abundantly expressed in the human endometrium, suggesting that uterine expression of CaBP-28k may be involved in reproductive function during the human menstrual cycle.     

Effect of sex and ovarian hormones on carotid baroreflex resetting and function during dynamic exercise in humans

To date, no studies have examined whether there are either sex- or ovarian hormone-related alterations in arterial baroreflex resetting and function during dynamic exercise. Thus we studied 16 young men and 18 young women at rest and during leg cycling at 50% heart rate (HR) reserve. In addition, 10 women were studied at three different phases of the menstrual cycle. Five-second pulses of neck pressure (NP) and neck suction (NS) from +40 to -80 Torr were applied to determine full carotid baroreflex (CBR) stimulus response curves. An upward and rightward resetting of the CBR function curve was observed during exercise in all groups with a similar magnitude of CBR resetting for mean arterial pressure (MAP) and HR between sexes (P > 0.05) and at different phases of the menstrual cycle (P > 0.05). For CBR control of MAP, women exhibited augmented pressor responses to NP at rest and exercise during mid-luteal compared with early and late follicular phases. For CBR control of HR, there was a greater bradycardic response to NS in women across all menstrual cycle phases with the operating point (OP) located further away from centering point (CP) on the CBR-HR curve during rest (OP-CP; in mmHg: -13 ± 3 women vs. -3 ± 3 men; P < 0.05) and exercise (in mmHg: -31 ± 2 women vs. -15 ± 3 men; P < 0.05). Collectively, these findings suggest that sex and fluctuations in ovarian hormones do not influence exercise resetting of the baroreflex. However, women exhibited greater CBR control of HR during exercise, specifically against acute hypertension, an effect that was present throughout the menstrual cycle.     

Opiatergic inhibition of pulsatile luteinizing hormone release during the menstrual cycle of rhesus macaques

The endogenous opioid peptides (EOPs) may inhibit the rate of hypothalamic gonadotropin-releasing hormone (GnRH) release and hence the frequency of pulsatile luteinizing hormone (LH) release, particularly in the luteal phase of the menstrual cycle. Our objectives were to compare the effects of an opiate antagonist, naloxone (NAL), on the patterns of LH, estradiol-17 beta (E2), and progesterone (P4) secretion during the follicular and luteal phases of the macaque menstrual cycle. Plasma levels of E2, P4, and bioactive LH were measured in serial, 15-min blood samples during 8-hr infusions of NAL (2 mg/hr) or saline, either on Days 5 or 6 of the follicular phase (FN and FS, n = 5 and 4, respectively) or on Days 8, 9, or 10 of the luteal phase (LN and LS, n = 5 each) of a menstrual cycle. The pulsatile parameters of each hormone were determined by PULSAR analysis and the correspondence of steroid pulses with those of LH were analyzed for each cycle stage in each animal. As expected, LH mean levels and pulse frequencies in LS monkeys were only about one-third of those values in FS animals. NAL had no effects on pulsatile LH, E2, or P4 release during the follicular phase. In contrast, luteal phase NAL infusions increased both LH mean levels and pulse frequencies to values which were indistinguishable from those in FS animals. LH pulse amplitudes did not differ among the four groups. Mean levels and pulse frequencies of P4 secretion in LS monkeys were about 4- and 14-fold greater than those values in FS animals. Mean levels and pulse amplitudes of P4 release in LN animals were greater than those values in all other groups. LH and E2 pulses were not closely correlated in follicular phase animals, and this pulse association was not altered by NAL. In FS monkeys, LH and P4 pulses were not correlated; however, NAL increased this LH-p4 pulse correspondence. LH and P4 pulses were closely correlated in luteal phase animals and this association was not affected by NAL. Our data suggest that the EOPs inhibit the frequency of pulsatile LH secretion in the presence of luteal phase levels of P4. During the midfollicular phase when LH pulses occur every 60 to 90 min, the opioid antagonist NAL alters neither the pulsatile pattern of LH release nor E2 secretion, but NAL may directly affect P4-secreting cells.     

17 beta-hydroxysteroid dehydrogenase activity in leiomyoma and myometrium and its relationship to concentrations of oestrone, oestradiol and progesterone throughout the menstrual cycle

The activity of the enzyme 17 beta-hydroxysteroid dehydrogenase (17 beta-OHSD) and concentrations of oestrone (E1), oestradiol (E2) and progesterone have been measured in leiomyoma and myometrium obtained at different stages of the menstrual cycle. Apart from conversion of E2 to E1 in the proliferative phase, no significant difference in enzyme activity was noted between normal and tumour tissue. However, interconversion in both tissues was shown to be higher in the secretory than the proliferative phase of the menstrual cycle. E1 concentrations were significantly higher (P less than 0.01) in leiomyoma than in myometrium, obtained during the proliferative phase. Concentrations of both oestrogens, in some tumour and normal tissues, were higher in the proliferative than the secretory phase. Secretory phase tissues contained higher concentrations of progesterone than those obtained in the proliferative phase of the menstrual cycle. Considerable differences in both enzyme activity and steroid concentrations were noted in different areas of the same tumour.     

Effects of time of day, gender, and menstrual cycle phase on the human response to a water load

Estrogen and progesterone interference with renal actions of arginine vasopressin (AVP) has been shown. Thus we hypothesized that women will have a higher water turnover than men and that the greatest difference will be during the luteal phase of the menstrual cycle. Seven men (32 +/- 3 yr) and six women (33 +/- 2 yr) drank 12 ml water/kg lean body mass on different days at 0800 and at 2000 following 10 h of fast and a standardized meal at 0600 and 1800. Women participated on days 4-11 and 19-25 of the menstrual cycle. Initial urine and plasma osmolalities and urine flow rates were similar in all experiments. The cumulative urine voided over 3 h following the morning drink was less in men (73 +/- 12% of the water load) compared with women in either the follicular (100 +/- 3%) or luteal phases (102 +/- 10%) of the menstrual cycle. Nighttime values (30-43% of the water load) were lower in all experiments and were not different between sexes or menstrual cycle phases. Plasma AVP was higher at night and may contribute to this diurnal response. The data are generally consistent with the stated hypothesis; however, possibly owing to the greatly reduced urine flow in both sexes at night, a difference between sexes was not observed at that time.     

Relationship between estradiol and progesterone concentrations and cognitive performance in normally cycling female cynomolgus monkeys

Preclinical research has demonstrated that cognitive function may be influenced by estradiol (E2) and progesterone (P4) concentrations, although few cognition studies involve normally cycling females. The present study examined cognitive performance in normally cycling female cynomolgus macaques (n = 14), a species with similarities to humans in brain organization and a nearly identical menstrual cycle to women. Initial assessments compared cognitive measures to circulating concentrations of E2 and P4 (n = 12). Once a relationship was characterized between hormones and cognitive performance, the menstrual cycle was divided into four distinct phases: early follicular (EF), late follicular (LF), early luteal (EL) and late luteal (LL), verified by the onset of menses and serum concentrations of E2 and P4. Concentrations of E2 were highest during the LF phase and P4 concentrations peaked during the EL phase. All monkeys were trained on two cognitive tasks: reversal learning, involving simple discrimination (SD) and reversal (SDR), which measured associative learning and behavioral flexibility, respectively (n = 3–4 per phase) and a delayed match-to-sample (DMS) task which assessed working memory (n = 11). P4 concentrations were positively correlated with number of trials and errors during acquisition of SD performance, but not during acquisition of the SDR task or maintenance of the reversal-learning task. Across the menstrual cycle, significantly fewer errors were made in the SDR task during the LF phase, when E2 concentrations were high and P4 concentrations low. Working memory, assessed with the DMS task, was not consistently altered based on previously characterized menstrual cycle phases. These findings demonstrate a relationship between P4, E2 and cognitive performance in normally cycling cynomolgus monkeys that is task dependent. Knowledge of these interactions may lead to a better understanding of sex-specific cognitive performance.     

Growth hormone secretion after baclofen administration in different phases of the menstrual cycle in healthy women

AIM: The aim of this study was to investigate the effect of baclofen administration on growth hormone (GH) secretion during different phases of the menstrual cycle. METHODS: Twelve healthy women (33.6 +/- (SD) 2.8 years; range 23-40 years) with regular menstrual cycles were enrolled. The phases of the menstrual cycle were determined using transvaginal ultrasonography (TV-US) and detecting hormonal serum levels. Plasma GH levels were evaluated during the early follicular, periovulatory and luteal phases of the cycle before and after the baclofen challenge test. RESULTS: After acute baclofen administration, GH levels increased significantly (p < 0.001) compared to basal values during the periovulatory and luteal phases, while no significant variation was detected during the early follicular phase. In addition, plasma GH levels resulted significantly (p < 0.001) higher during the luteal phase than during the periovulatory phase. CONCLUSION: Acute baclofen administration induces a significant increase in plasma GH levels in healthy females during the periovulatory and luteal phases, but not during the early follicular phase. These data suggest a modulator role of plasma sex steroids levels on GH release induced by baclofen.     

The Effects of Sex Hormonal Fluctuations during Menstrual Cycle on Cortical Excitability and Manual Dexterity (a Pilot Study)

Aim

To investigate whether hormonal fluctuations during the menstrual cycle affect corticospinal excitability, intracortical inhibition (ICI) or facilitation (ICF) in primary motor cortex, and also whether the hormonal fluctuations have any effect on manual dexterity in neurologically intact women.

Materials and Methods

Twenty volunteers (10 Female, 10 Male) were included in this study. The levels of progesterone and estradiol were measured from saliva during the women’s menstrual follicular, ovulation and mid-luteal phases. Motor evoked potentials were recorded from the right first dorsal interosseous muscle. Single and paired-pulse Transcranial Magnetic Stimulation (TMS) were delivered in a block of 20 stimuli. With paired-pulse technique, 3ms and 10ms inter-stimulus intervals were used to assess ICI and ICF, respectively. The Grooved Pegboard Test (GPT) was completed in each session before the TMS assessments. Male participants were tested at similar time intervals as female participants.

Results

Mixed design ANOVA revealed that GPT score in female participants was significantly lower at the mid-luteal phase compared to the ovulation phase (p = 0.017). However, it was not correlated with progesterone or estrogen fluctuations during the menstrual cycle. The results also showed that the effect of phase, sex and the interaction of phase by sex for resting motor threshold, ICI or ICF were not significant (p > 0.05).

Conclusion

Manual dexterity performance fluctuates during the menstrual cycle in neurologically intact women, which might be due to the balance of the neuromodulatory effects of P4 and E2 in the motor cortex during different phases.     

Effects of the menstrual cycle on auditory event-related potentials

Gonadal steroids (estradiol and progesterone) can alter neuronal functioning, but electrophysiological evidence in women is still sparse. Therefore, the present study investigated event-related potentials (ERPs) to neutral stimuli over the course of the menstrual cycle. In addition, associations between ERPs and salivary estradiol and progesterone concentrations were investigated. Eighteen young healthy women were tested at three different phases of their menstrual cycle (menses, and follicular and luteal phases). ERPs (i.e., the N1 and P2 components, reflecting cortical arousal and the orienting response, the N2, P3, and the Slow Wave (SW), reflecting controlled processing) were measured using two different paradigms. In the luteal phase, early ERPs reflecting the cortical arousal response were diminished in the first stimulus block indicating an attenuated orienting response. These changes were significantly correlated with estradiol as well as progesterone levels. As to the later ERP components, the N2 latency was shorter during menses compared to the other two phases. No menstrual cycle-associated changes were apparent in other late ERP components. In sum, this study documents changes in auditory ERPs across the menstrual cycle with the most prominent changes occurring during the luteal phase. Future ERP studies therefore need to be more attentive to the issue of menstrual phase when studying female subjects or female patients.     

Concentration of plasminogen activators and inhibitor in the human endometrium at different phases of the menstrual cycle.

The concentrations of tissue plasminogen activator (t-PA), urokinase plasminogen activator (u-PA) and plasminogen activator inhibitor (PAI-1) have been determined in endometrial curettings obtained from 46 subfertile women during proliferative, early or late secretory phases of the menstrual cycle. t-PA activity and antigen concentrations was significantly higher (P < 0.001) in late secretory endometrium than in proliferative or early secretory endometrium. Higher concentrations of PAI-1 antigen (P < 0.05) were also noted in late secretory phase than in proliferative and early secretory endometrium. However, u-PA concentration was not significantly different and no PAI activity could be demonstrated in the menstrual phases studied. Zymography studies confirmed the presence of both t-PA and u-PA in the endometrium. Ovarian hormonal patterns may therefore influence the activity of plasminogen activators especially of t-PA in the endometrium during various phases of the menstrual cycle.     

Variations in plasma selenium levels as a result of the menstrual cycle and pregnancy in healthy Japanese women

Plasma levels of selenium (Se) were determined consecutively during a menstrual cycle of six women in three phases (i.e., menses, follicular, and luteal). To detect possible differences in relation to normal pregnancy, plasma levels of Se were also determined in paired samples of maternal and umbilical cord blood from 12 pregnant women. No periodic changes in the plasma Se levels were observed during the menstrual cycle. The intraindividual variation, estimated by coefficients of variation, ranged from 1.9% to 9.9% among the menstrual phases of the subjects. The plasma Se level during pregnancy did not differ significantly from those of nonpregnant women, and those in the second trimester and at delivery were at similar levels (1.58+/-.14 and 1.48+/-.20 mmol/L, respectively). Compared to the levels of maternal Se at delivery, the fetal cord plasma at birth had a significant lower Se level (1.23+/-.34 mmol/L, p<.05).     

No effect of menstrual cycle phase on glucose kinetics and fuel oxidation during moderate-intensity exercise

Resting and exercise fuel metabolism was assessed in three different phases of the menstrual cycle, characterized by different levels of estrogen relative to progesterone: early follicular (EF, low estrogen and progesterone), midfollicular (MF, elevated estrogen, low progesterone), and midluteal (ML, elevated estrogen and progesterone). It was hypothesized that exercise glucose utilization and whole body carbohydrate oxidation would decrease sequentially from the EF to the MF to the ML phase. Normal-weight healthy females, experiencing a regular menstrual cycle, were recruited. Subjects were moderately active but not highly trained. Testing occurred after 3 days of diet control and after an overnight fast (12-13 h). Resting (2 h) and exercise (50% maximal O(2) uptake, 90 min) measurements of whole body substrate oxidation, tracer-determined glucose flux, and substrate and hormone concentrations were made. No significant difference was observed in whole body fuel oxidation during exercise in the three phases (nonprotein respiratory exchange ratio: EF 0.84 +/- 0.01, MF 0.85 +/- 0.01, ML 0.85 +/- 0.01) or in rates of glucose appearance or disappearance. There were, however, significantly higher glucose (P < 0.05) and insulin (P < 0.001) concentrations during the first 45 min of exercise in the ML phase vs. EF and MF phases. In conclusion, whole body substrate oxidation and glucose utilization did not vary significantly across the menstrual cycle in moderately active women, either at rest or during 90 min of moderate-intensity exercise. During the ML phase, however, this similar pattern of substrate utilization was associated with greater glucose and insulin concentrations. Both estrogen and progesterone are elevated during the ML phase of the menstrual cycle, suggesting that one or both of these sex steroids may play a role in this response.     

Fatty acid reesterification but not oxidation is increased by oral contraceptive use in women.

We evaluated the hypothesis that fatty acid reesterification would be increased during rest and exercise in the midluteal menstrual cycle phase and during oral contraceptive use, when ovarian hormone concentrations are high, compared with the early follicular phase. Subjects were eight moderately active, weight-stable, eumenorrheic women (24.8 +/- 1.2 yr, peak oxygen consumption = 42.0 +/- 2.3 ml.kg(-1).min(-1)) who had not taken oral contraceptives for at least 6 mo. Plasma free fatty acid (FFA) kinetics were assessed in the 3-h postprandial state by continuous infusion of [1-(13)C]palmitate and [1,1,2,3,3-(2)H]glycerol during 90 min of rest and 60 min of exercise at 45% and 65% peak oxygen consumption in the early follicular and midluteal menstrual cycle phases and during the inactive- and high-dose phases following 4 mo of oral contraceptive use. Plasma FFA rates of appearance, disappearance, and oxidation increased significantly from rest to exercise with no differences noted between menstrual cycle or oral contraceptive phases or exercise intensities. Compared with either menstrual cycle phase, oral contraceptive use resulted in an increase in plasma-derived fatty acid reesterification and a decrease in the proportion of plasma FFA rate of disappearance that was oxidized at rest and during exercise. Endogenous and exogenous synthetic ovarian hormones do not exert a measurable influence on plasma FFA turnover or oxidation at rest or during moderate-intensity exercise in the 3-h postprandial state when carbohydrate use predominates. The increase in whole body lipolytic rate during exercise noted previously with oral contraceptive use is not matched by an increase in fatty acid oxidation and results in an increase in reesterification. Synthetic ovarian hormones contained in oral contraceptives increase lipolytic rate, but fatty acid oxidation during exercise is determined by exercise intensity and its metabolic and endocrine consequences.     

Menstrual status and plasma vasopressin, renin activity, and aldosterone exercise responses

The effects of menstrual cycle phase (early follicular vs. midluteal) and menstrual status (eumenorrhea vs. amenorrhea) on plasma arginine vasopressin (AVP), renin activity (PRA), and aldosterone (ALDO) were studied before and after 40 min of submaximal running (80% maximal O2 uptake). Eumenorrheic runners were studied in the early follicular and midluteal phases determined by urinary luteinizing hormone and progesterone and plasma estradiol and progesterone assays; amenorrheic runners were studied once. Menstrual phase was associated with no significant differences in preexercise plasma AVP or PRA, but ALDO levels were significantly higher during the midluteal phase than the early follicular phase. Plasma AVP and PRA were significantly elevated at 4 min after the 40-min run in the eumenorrheic runners during both menstrual phases and returned to preexercise levels by 40 min after exercise. Plasma ALDO responses at 4 and 40 min after exercise were higher in the midluteal phase than the early follicular phase. Menstrual status was associated with no significant differences in preexercise AVP or PRA; however, ALDO levels were significantly higher in the amenorrheic runners. After exercise, responses in the amenorrheic runners were comparable with the eumenorrheic runners during the early follicular phase. Thus, submaximal exercise elicits significant increases in plasma AVP and PRA independent of menstrual phase and status. However, plasma ALDO is significantly elevated during the midluteal phase, exercise results in a greater response during this menstrual phase, and amenorrheic runners have elevated resting levels of ALDO.     

Morphology of the oviducts and endometria of cynomolgus macaques during the menstrual cycle

We sampled the reproductive tracts of 27 cynomolgus macaques during the menstrual cycle and correlated the cytologic changes in the oviductal epithelium with changes in the serum levels of estradiol (E2) and progesterone (P) and with the histology of the ovaries and the endometria. We identified an orderly sequence of changes in the oviductal epithelium from the early follicular to the late luteal phase, and we classified this sequence into eight stages, named as follows: preciliogenic, ciliogenic, ciliogenic-ciliated, ciliated-ciliogenic, ciliated-secretory, early regression, late regression and full regression. The preciliogenic and ciliogenic phases were coincident with menses and the early follicular phase. The ciliogenic-ciliated, ciliated-ciliogenic and ciliated-secretory phases during which the oviductal epithelium became progressively more differentiated were coincident, respectively, with the midfollicular, late follicular and periovulatory phases of the cycle. The early, late and full regression stages during which the epithelium became progressively more atrophied, deciliated and nonsecretory were coincident, respectively, with the early, mid and late luteal phases of the cycle. The cyclic changes in the endometrium of cynomolgus macaques were similar to those reported for the rhesus macaque.     

Aquaporin-2 expression in human endometrium correlates with serum ovarian steroid hormones

The aim of the present study was to examine the expression of aquaporin-2 (AQP2), a member of the water channel family aquaporins (AQPs), in human uterine endometrium and its modulation of ovarian steroid hormone at the proliferative and secretory phases. Western blot, immunohistochemistry, and RT-PCR were employed in the present study. Western blot revealed a 29-kDa band that represented AQP2 in human endometrium. The expression of AQP2 in endometrium was confirmed by RT-PCR and immunohistochemical results. The immunohistochemical analysis demonstrated that AQP2 was prominent in luminal and glandular epithelial cells of endometrium. The levels of endometrial AQP2 expression changed during the menstrual cycle and were higher in the secretory endometrium than in the proliferative endometrium. A significantly high level of AQP2 was detected at the mid-secretory phase. There was a positive correlation between the levels of the endometrial AQP2 expression and the concentrations of the serum 17beta-estradiol (E2) or/and progesterone (P4). These data for the first time corroborate that AQP2 is expressed in human endometrium and that the expression of AQP2 in human endometrium might be regulated by E2 or/and P4. The changed expression of AQP2 at different phases of the menstrual cycle may be essential to reproductive physiology in human. The high level of endometrial AQP2 expression was observed at the mid-secretory phase, the time of embryo implantation, suggesting that AQP2 might play physiological roles in the uterine receptivity.     

The resting frontal alpha asymmetry across the menstrual cycle: a magnetoencephalographic study

Gonadotropic hormones play an important role in the regulation of emotion. Previous studies have demonstrated that estrogen can modulate appetitive (approach/positive) and aversive (avoidance/negative) affective behaviors during the menstrual cycle. Frontal alpha asymmetry (a measure of relative difference of the alpha power between the two anterior hemispheres) has been associated with the trait and state reactivity of different affective styles. We studied the pattern change of frontal alpha asymmetry across the menstrual cycle. 16 healthy women participated in this resting magneto-encephalographic (MEG) study during the peri-ovulatory (OV) and menstrual (MC) phases. Our results showed significant interaction of resting MEG alpha activity between hemispheric side and menstrual phases. Difference in spontaneous frontal alpha asymmetry pattern across the menstrual cycle was also noted. Relatively higher right frontal activity was found during the OV phase; relatively higher left frontal activity was noted during the MC phase. The alteration of frontal alpha asymmetry might serve a sub-clinical correlate for hormonal modulation effect on dynamic brain organization for the predisposition and conceptualization of different affective styles across the menstrual cycle.