The purpose of this study was to examine the effects of menstrual cycle phase on myofiber injury, regenerative events and inflammation after electrical-stimulation (ES) induced myofiber damage. 28 premenopausal women (21.3 ± 2 yrs) were randomized into an early follicular (EF; N=14) or late follicular (LF; N = 14) group. After menstrual cycle tracking and phase confirmation, subjects underwent 200 electrically stimulated eccentric muscle contractions one week after providing a muscle biopsy. 7 days post-ES, subjects provided a final biopsy. Primary outcomes included: serum estradiol, indirect markers of muscle damage, direct indicators of myofiber necrosis and regeneration, satellite cell number, and macrophage infiltration. Women in the LF group had higher serum estradiol (122.1 ± 23.4 vs. 81.7 ± 30.8 pg/ml; P<0.001)compared to the EF group on the day of ES. Whereas the EF group recovered baseline maximal isometric strength by 4 days post-ES, the LF group did not. Only women in the LF group showed significant and consistent evidence of myofiber necrosis and regeneration pre- to post-ES. Despite showing more evidence of myofiber damage, women in the LF group also experienced reduced total and CD206+ macrophage infiltration relative to the EF group. Satellite cell quantity increased significantly post-ES in both groups, with no differences between groups. Collectively, the data suggest that the high estrogen LF phase may be associated with increased susceptibility to myofiber injury while also limiting the subsequent intramuscular inflammatory response.

During the luteal and follicular phases of the estrous cycle, cumulus-oocyte complexes (COC) and oviduct epithelial cells (OEC) undergo notable physiological and morphological changes. Maintaining proper zinc (Zn) homeostasis is crucial in both somatic and germinal mammalian cells. This study aimed to assess the impact of the estrous phase (luteal or follicular) on Zn transporter expression in bovine COC and OEC (BOEC). The expression of Zn transporters Slc39a6 (ZIP6), Slc39a8 (ZIP8), Slc39a14 (ZIP14), Slc30a3 (ZnT3), Slc30a7 (ZnT7), and Slc30a9 (ZnT9) was analyzed in COC and BOEC from cows during the luteal or follicular phases. Gene expression of ZIP6, ZIP14, and ZnT9 was quantified in COC and BOEC. The gene expression in the remaining transporters could not be quantified due to low mRNA levels (ZIP8 and ZnT3 in COC and BOEC; ZnT7 in BOEC) or absence of expression (ZnT7 in COC). In COC, the relative expression (RE) of all three transporters was higher in the luteal phase compared to the follicular phase (P ≤ 0.05). In BOEC, the luteal phase increased the RE of ZIP 6 (P ≤ 0.05), decreased the RE of ZnT9 (P ≤ 0.05), and did not modify the RE of ZIP14 (P > 0.05) compared to the follicular phase. In conclusion, the study reveals differences in the gene expression of ZIP6, ZIP14, and ZnT9 according to the estrous cycle phase in ex vivo samples of bovine COC and OEC.

BACKGROUND: A recent study by our group found that women displayed greater attentional bias to alcohol-related cues during the late versus early follicular phase in both sober and intoxicated states, suggesting a greater risk of excessive drinking among women during this phase. Changes in attentional bias as a function of menstrual cycle phase raise questions about potential sex differences in the relative consistency by which women and men display attentional bias to alcohol over time.
OBJECTIVE: The present study tested sex differences in attentional bias to alcohol by comparing the change in women\'s attentional bias from early to late follicular phase to that observed in men over the same period.
METHODS: Twenty-five men and 25 women aged 21-32 participated in a placebo-controlled study examining sex differences in the rewarding properties of alcohol. Participants completed measures of attentional bias to alcohol-related cues during two sessions following both 0.6 g/kg alcohol and placebo. Test sessions occurred one week apart, and for female participants coincided with the early and late follicular phases.
RESULTS: Men consistently displayed attentional bias to alcohol-related cues across sessions under both doses. By contrast, women showed attentional bias only during the late follicular phase, at a magnitude greater than that observed in men, and persistent under both doses.
CONCLUSIONS: These findings highlight the potential role of sex and menstrual cycle phase in sensitizing drinkers to rewarding properties of alcohol-related cues. Men\'s motivation to drink may remain relatively consistent, whereas women may be most motivated during the late follicular phase.

Successful reproductive management of domestic mammals depends primarily upon timely identification of oestrous cycle stages. There is a need to develop an alternative non-invasive, welfare-friendly, accurate and reliable method to identify reproductive cycle stages. This is of particular interest for horse breeders, because horses are high-value farm animals that require careful management and individual monitoring. Saliva sampling is non-invasive, painless and welfare-friendly. Thus, we performed a metabolomic analysis of equine saliva during different reproductive stages to identify changes in the salivary metabolome during anoestrus, the oestrous cycle and early gestation. We compared the saliva and plasma metabolomes to investigate the relationship between the two fluids according to the physiological stage. We collected saliva and plasma samples from six mares during seasonal anoestrus, during the follicular phase 3 days, 2 days and 1 day before ovulation and the day when ovulation was detected, during the luteal phase 6 days after ovulation, and during early gestation 18 days after ovulation and insemination. Metabolome analysis was performed by proton-nuclear magnetic resonance spectroscopy. We identified 58 and 51 metabolites in saliva and plasma, respectively. The levels of four metabolites or groups of metabolites in saliva and five metabolites or groups of metabolites in plasma showed significant modifications during the 4 days until ovulation, ie 3 days prior to and on the day of ovulation. The levels of 11 metabolites or groups of metabolites in saliva and 17 metabolites or groups of metabolites in plasma were significantly different between the seasonal anoestrus and the ovarian cyclicity period. The physiological mechanisms involved in the onset of ovarian cyclicity and in ovulation induced modifications of the metabolome both in plasma and saliva. The metabolites whose salivary levels changed during the reproductive cycle could be potential salivary biomarkers to detect the reproductive stage in a welfare friendly production system. In particular, we propose creatine and alanine as candidate salivary biomarkers of ovulation and of the onset of ovarian cyclicity, respectively. However, extensive validation of their reliability is required. Our study contributes to extend to domestic mammals the use of saliva as a non-invasive alternative diagnostic fluid for reproduction in a welfare-friendly production system.

Difficulties in fear regulation can sometimes result in maladaptive fear responses. To better understand how to improve fear regulation, it is important to determine how known factors, such as sex hormone status and stress, might interact to influence fear memory. Research has shown that women with high estradiol levels (mid-cycle) and men exhibit better extinction retention compared to women with low estradiol levels (women in the early follicular cycle or using oral contraceptives). Stress has also been demonstrated to affect both the learning and retention of extinction. Despite documented interactions between stress and sex hormones, their combined effects have not been thoroughly studied. This study aims to examine the impact of stress as a function of sex hormone status on extinction learning and retention. A total of 168 non-clinical participants were studied, including men (n = 46), women using oral contraceptives (n = 38), women in the early follicular phase (n = 40), and women in mid-cycle (n = 44). On Day 1, fear acquisition training was performed. On day 2, prior to extinction training, half of the participants were exposed to a psychosocial stressor, while the other half performed a non-stressful control task. On day 3, extinction retention was tested. Fear was quantified using skin conductance responses, while stress hormones were quantified through saliva samples. Exposure to stress prior to extinction training did not affect extinction learning, regardless of sex hormone status. In contrast, pre-extinction stress exposure had different effects on extinction retention depending on hormone status. Stressed men showed impairment in extinction retention compared to controls, while the experimental condition had no effect on naturally cycling women. Regardless of stress exposure, early follicular women exhibited a deficit in fear regulation, while mid-cycle women showed effective fear regulation. Among women using oral contraceptives, the stress group demonstrated better extinction retention compared to the control group. These results demonstrate the importance of considering sex hormone status and stress exposure during extinction learning, as both components may modulate extinction retention. These results could help identifying hormonal conditions that may enhance the effectiveness of extinction-based psychological therapies used in the treatment of fear-related disorders.

The effects of female sex hormones on optimal performance have been increasingly recognized as an important consideration in exercise and sport science research. This narrative review explores the findings of studies evaluating the effects of menstrual cycle phase in eumenorrheic women and the use of hormonal contraception (oral contraceptives and hormonal intrauterine devices) on metabolism, muscular strength, and recovery in active females. Ovarian hormones are known to influence metabolism because estrogen is a master regulator of bioenergetics. Importantly, the menstrual cycle may impact protein synthesis, impacting skeletal muscle quality and strength. Studies investigating muscular strength in eumenorrheic women report equivocal findings between the follicular phase and luteal phase with no differences compared to oral contraceptive users. Studies examining recovery measures (using biomarkers, blood lactate, and blood flow) do not report clear or consistent effects of the impact of the menstrual cycle or hormonal contraception use on recovery. Overall, the current literature may be limited by the evaluation of only one menstrual cycle and the use of group means for statistical significance. Hence, to optimize training and performance in females, regardless of hormonal contraception use, there is a need for future research to quantify the intra-individual impact of the menstrual cycle phases and hormonal contraceptive use in active females.

Testosterone production in women is thought to systematically shift across the menstrual cycle, peaking during the mid-cycle ovulatory window, and potentially influencing women\'s behavior. Testosterone is a molecular intermediary to the production of estradiol, which is necessary for ovulation to occur, but the amount of testosterone escape and exposure to the peripheral tissues is not fully understood. Salivary testosterone is a common biomarker in behavioral neuroendocrinological studies and is thought to reflect the bioactive portions in serum. In N = 339 women with confirmed ovulation via luteinizing hormone tests, salivary testosterone, assayed with LC-MS/MS, was sampled four times across the mid-cycle ovulatory window the luteal phase. Within-subject analysis revealed a significant but small pattern of a mid-cycle peak and a luteal decrease at the aggregate level. However, at the individual level, there was substantial variability in the direction and magnitude of the testosterone-cycle pattern. We discuss the relevant underlying physiology, background research, issues with assay methodolody, and considerations for researchers studying testosterone levels in women.

A single bout of exercise enhances executive function (EF) and may relate to an increase in cerebral blood flow (CBF). A limitation in the current literature is that biologically female participants are underrepresented given some evidence that changes in hormone levels across the menstrual cycle impact physiological and psychological variables. Here, biologically female participants completed separate single bouts of moderate intensity exercise (80% of estimated lactate threshold) during the follicular (FOL) and luteal (LUT) phases of their menstrual cycle. In addition, biologically male participants completed a same duration/intensity exercise session. Middle cerebral artery velocity (MCAv) was used to estimate CBF and pre- and postexercise EF was assessed via the antisaccade task. Results showed that resting MCAv was larger in the LUT than FOL phase; however, the exercise-mediated increase in MCAv was equivalent between menstrual cycle phases, and between female and male participants. Antisaccade reaction times reliably decreased from pre- to postexercise and frequentist and non-frequentist statistics demonstrated that the magnitude of the decrease was equivalent across FOL and LUT phases, and between female and male participants. Thus, results evince that menstrual cycle status should not serve as a basis limiting biologically female participants\' inclusion in research examining exercise and EF.

Oral contraceptive (OC) use can increase resting blood pressure (BP) in females as well as contribute to greater activation of group III/IV afferents during upper body exercise. It is unknown, however, whether an exaggerated BP response occurs during lower limb exercise in OC users. We sought to elucidate the group III/IV afferent activity-mediated BP and heart rate responses while performing lower extremity tasks during early and late follicular phases in young, healthy females. Females not taking OCs (NOC: n = 8; age: 25 ± 4 yr) and those taking OCs (OC: n = 10; age: 23 ± 2 yr) completed a continuous knee extension/flexion passive stretch (mechanoreflex) and cycling exercise with subsystolic cuff occlusion (exercise pressor reflex), which was followed by a 2-min postexercise circulatory occlusion (PECO) (metaboreflex). Data collection occurred on two occasions: once during the early follicular phase (days 1-4) and once during the late follicular phase (days 10-14) of their menstrual cycle (NOC) or during the placebo and active pill phases (OC). Resting mean arterial BP and heart rate were not different between phases in NOC and OC participants (P > 0.05). Hemodynamic responses to metaboreflex, mechanoreflex, and collective exercise pressor reflex activation were not different between phases in both groups (P > 0.05). In conclusion, although OCs are known to increase BP at rest, our findings indicate that neither endogenous nor exogenous (OC) sex hormones modulate BP during large, lower limb muscle exercise with or without group III/IV afferent activation in young, healthy females.NEW & NOTEWORTHY Sex differences in the cardiovascular response to exercise have been demonstrated and may be dependent on sex hormone levels. Furthermore, oral contraceptives (OCs) have been shown to exaggerate the blood pressure response to upper extremity exercise. The results of this study indicate that neither endogenous nor exogenous (OC) sex hormones modulate BP during lower extremity dynamic exercise or with group III/IV afferent activation in young, healthy females.

UNASSIGNED: Some synthetic dyes used mainly in textile industries have been associated with endocrine disruption, resulting in infertility, among other disorders. It is unknown if occupational exposure to Vat textile dyes among premenopausal dyers alters hormonal levels.
UNASSIGNED: We aimed at determining the probable effects of occupational exposure to Vat dyes on reproductive hormones of female textile dyers in the follicular and luteal phases while relating this to age categories and duration of exposure.
UNASSIGNED: Thirty-three premenopausal Vat textile dyers at \"Itoku\", Abeokuta, Nigeria, among a population of about 80 female dyers were age and sex-matched with 55 non-exposed (control) female participants. Using semi-structured questionnaires, socio-demographic, occupational details and the LMP of participants were obtained. Serum samples were collected in follicular and luteal phases and assayed for female sex hormones using Enzyme Immunoassay. Mann-Whitney U and Z- statistic were used for comparison of the two groups. P-value < 0.05 was considered to be significant.
UNASSIGNED: In the follicular phase, the result showed a lower mean FSH ranking (in age category ≤20 years) and higher (p<0.05) Estradiol ranking (in age category 31-40 years) in the exposed than the unexposed. Mean ranks of Progesterone and Estradiol in the luteal phase (age category 31-40 years) were higher (p<0.05) in the exposed, while Estradiol (age category ≥41years) ranked lower (p<0.05). Prolactin demonstrated a significant inverse relationship with the duration of exposure.
UNASSIGNED: Occupational exposure to Vat dye among female dyers in Abeokuta is associated with some sex hormone disruption which appears to be age and duration of exposure-related.