Female Reproductive Cycle Research Articles

Duration of the seminiferous epithelium cycle in the frugivorous bat Artibeus lituratus

The seminiferous epithelium goes through multiple changes which enables the differentiation of a spermatogonia in a fully mature spermatozoon. The timing of these changes is species-specific and influences the duration of the reproductive cycles. Bats are among wild mammals whose coordination between male and female reproductive cycles are imperative, since most females show seasonal preferences, even in the Tropics. This seasonal variation demands constant sperm production ready for spermiation in order to guarantee its genetic dispersion and reproduction success. Despite their abundance, little is known about the duration of reproductive cycles in Neotropical bat species, a relevant information for the species management and for conservational strategies regarding anthropogenic and climate influences on bats reproduction. In this study, we aimed at characterizing the stages of the seminiferous epithelium cycle (SEC) of the fruit bat Artibeus lituratus and to determine its duration based on the immunohistochemical analysis of the bromodeoxyuridine (BrDU) activity. SEC stages were characterized according to the tubular morphology method and the frequency of each stage was estimated. After intratesticular injections of BrDU, the animals were euthanized at different times, and the estimation of SEC duration was performed by observing the most advanced germ cells in the seminiferous epithelium. The most advanced stained cells after 2 days of BrdU injection were the primary spermatocytes in pachytene, transitioning from stages 1–2 of the SEC. Within 2 days, we found a progression of 30.42% of the SEC, and an entire cycle lasted 6.58 days on average. Considering that 4.5 seminiferous epithelium cycles are necessary for the whole spermatogenic processes to be completed, the total length of spermatogenesis in A. lituratus was estimated at 29.61 days. Our findings support a pattern of bimodal seasonal polyestry for this species, with rapid spermatogenic cycles.

Efeito de Artemisia L. (Asteraceae) no ciclo reprodutivo feminino: uma revisão

A sociedade moderna desenvolveu uma dependência da alopatia para o controle da maioria das doenças e, no caso das mulheres, de seu ciclo reprodutivo e minimização dos sintomas associados. Havendo, entretanto, uma crescente adesão à fitoterapia. Artemisia L. é recorrentemente citada em levantamentos etnobotânicos como reguladora da fertilidade. A presente revisão compilou resultados de experimentos sobre o efeito das espécies desse gênero no ciclo reprodutivo feminino, visando compreender seus mecanismos de ação. A revisão bibliográfica foi feita a partir das bases de dados PUBMED, LILACS, SciELO e Portal de Periódicos da CAPES. Foram selecionados 12 artigos sobre sete espécies de Artemisia (A. absinthium L., A. annua L., A. dracunculus L., A. herba-alba Asso, A. kopetdaghensis Krasch., Popov & Lincz. ex Poljakov, A. monosperma Delile e A. vulgaris L), sendo identificados os seguintes efeitos sobre o organismo materno e a prole: desequilíbrio hormonal, diminuição da fertilidade, atividade anti-implantação e embriofetotoxicidade. Considerando o potencial desse gênero como contraceptivo e interruptor gestacional, adverte-se sobre o perigo do consumo por gestantes e sugere-se um aprofundamento dos estudos etnofarmacológicos para que suas propriedades sejam aproveitadas em futuros derivados.

Reproductive cycle of Aplodinotus grunniens females (Rafinesque, 1819) in the Usumacinta River, Mexico

The freshwater drum Aplodinotus grunniens is a species widely distributed in North America. In the Mexican southeast, this species occurs in the Usumacinta River, where it supports an artisanal fishery. In this regard, the present study was conducted to supply detailed information on the female reproductive cycle of this species. Calculations of gonadosomatic (GSI) and hepatosomatic (HSI) indexes, histological and visual staging of ovaries as well as the staging of oocyte development were applied together to determine the reproductive changes during an annual cycle. The histological analysis revealed the presence of spawning capable females throughout the year, and the distribution frequencies of oocyte diameters displayed the continuous occurrence of mature oocytes, with great data dispersion and different modal groups. These observations were further corroborated by the presence of alternating peaks and drops in the GSI and HSIs, which were correlated with the occurrence of maturing and spawned females. These data, taken together, reveal that A. grunniens from the Usumacinta River is a partial spawner with asynchronous ovarian development and undetermined fecundity that reproduces year-round, but with spawning occurring preferably during the rainfall-flooding season (June to November). The Usumacinta River seems to be a permanently favorable environment for sheltering, feeding and growth of A. grunniens broods, especially during the flooding season. The information generated in this study will be useful for the development of management strategies in the wild as well as for the exploration of A. grunniens as a potential species for aquaculture production in southern Mexico.

Effects of temperature on the reproductive physiology of female elasmobranchs: The case of the narrownose smooth-hound shark (Mustelus schmitti)

The knowledge of how temperature influences elasmobranchs reproductive physiology allows a better understanding of their reproductive patterns. This study describes the relationship between temperature fluctuations and the plasmatic changes of the sex steroids related to reproduction: testosterone (T), estradiol (E2) and progesterone (P4), throughout the female reproductive cycle of the shark Mustelus schmitti. A total of 123 adult females were bi-monthly sampled in Buenos Aires, Argentina, coastal waters. Bottom temperatures were recorded at each sampling point and blood samples were taken from each female for plasma sex steroids measurement. Sex steroid plasma levels were analyzed in relation with maximum follicular diameter (MFD), uterosomatic index (USI, as indicator of pregnancy) and temperature using Generalized Additive Models. Plasmatic E2 and T increased during follicular growth until MFD reached 1.34 and 1.46 cm, respectively. Peak of T occurred at the follicular stage associated with parturition (MFD, 1.4–1.6 cm), just prior to final maturation and ovulation (MFD, 1.6–2.0 cm). Progesterone significantly increased at this last ovarian phase, while T and E2 decreased. The increase of USI with pregnancy was associated to a decrease in T and mainly E2 levels, while P4 remained unaffected. Prior to ovulation, T plasma levels decreased with temperature below to 13 °C and then increased progressively with a pronounced elevation above 17 °C, while E2 presented an opposite pattern. Progesterone plasma levels changed with temperature showing a similar pattern to that observed for T. Using M. schmitti shark as model species, this study shows a clear picture of how seawater temperature variations can affect the reproductive physiology in elasmobranch females. A hypothetical mechanism (based on T elevation driven by temperature increase and its connection by feedback with a P4 rise and parturition/ovulation induction) is proposed as evidence to support that the increase in temperature can trigger reproductive events in elasmobranchs. In addition to its ecological scope, this work contributes to reinforce the relatively scarce general knowledge of elasmobranchs reproductive physiology.

Migration and reproduction are associated with similar degrees of phenotypic flexibility in an insectivorous bat.

As organisms face variation in energetic challenges and physiological demands, they often respond with reversible changes in behavior, physiology, and morphology, described as phenotypic flexibility. From the magnitude of phenotypic change, we can infer the energetic challenges of different life stages. We studied phenotypic flexibility in a population of reproductive and pre-migratory female insectivorous bats (Tadarida brasiliensis). While female reproductive demands are well described in insectivorous bats, there are questions regarding the demands of migration. Our objective was to measure phenotypic flexibility to assess the cost of autumn migration compared to reproduction in an insectivorous bat. We measured plasma triglycerides to quantify foraging rate, and body composition (body mass and individual organ mass) of T. brasiliensis throughout the summer season (from arrival in spring through pre-migration/migration departure in autumn) according to the female reproductive cycle. We found phenotypic changes during pre-migration/migration similar to periods of high-energy demand during reproduction (e.g., late pregnancy and lactation). Most notably, bats weighed as much during peak pregnancy, as they did during migration, and the rapid mass gain from post-lactation through the migratory period was due to a combination of hyperphagia and hypertrophy of digestive organs. Our results indicate that energetic demands incurred during migration are similar to those during reproduction and emphasize the energetic challenges of migration.

Membrane and nuclear initiated estrogenic regulation of homeostasis

Reproduction and energy balance are inextricably linked in order to optimize the evolutionary fitness of an organism. With insufficient or excessive energy stores a female is liable to suffer complications during pregnancy and produce unhealthy or obesity-prone offspring. The quintessential function of the hypothalamus is to act as a bridge between the endocrine and nervous systems, coordinating fertility and autonomic functions. Across the female reproductive cycle various motivations wax and wane, following levels of ovarian hormones. Estrogens, more specifically 17β-estradiol (E2), coordinate a triumvirate of hypothalamic neurons within the arcuate nucleus (ARH) that govern the physiological underpinnings of these behavioral dynamics. Arising from a common progenitor pool of cells, this triumvirate is composed of the kisspeptin (Kiss1ARH), proopiomelanocortin (POMC), and neuropeptide Y/agouti-related peptide (AgRP) neurons. Although the excitability of these neuronal subpopulations is subject to genomic and rapid estrogenic regulation, kisspeptin neurons are the most sensitive, reflecting their integral function in female fertility. Based on the premise that E2 coordinates autonomic functions around reproduction, we will review the recent findings on the synaptic interactions between Kiss1, AgRP and POMC neurons and how the rapid membrane-initiated and intracellular signaling cascades activated by E2 in these neurons are critical for control of homeostatic functions supporting reproduction.

PGC-1α induced browning promotes involution and inhibits lactation in mammary glands.

The PPARγ coactivator 1α (PGC-1α) is a transcriptional regulator of mitochondrial biogenesis and oxidative metabolism. Recent studies have highlighted a fundamental role of PGC-1α in promoting breast cancer progression and metastasis, but the physiological role of this coactivator in the development of mammary glands is still unknown. First, we show that PGC-1α is highly expressed during puberty and involution, but nearly disappeared in pregnancy and lactation. Then, taking advantage of a newly generated transgenic mouse model with a stable and specific overexpression of PGC-1α in mammary glands, we demonstrate that the re-expression of this coactivator during the lactation stage leads to a precocious regression of the mammary glands. Thus, we propose that PGC-1α action is non-essential during pregnancy and lactation, whereas it is indispensable during involution. The rapid preadipocyte-adipocyte transition, together with an increased rate of apoptosis promotes a premature mammary glands involution that cause lactation defects and pup growth retardation. Overall, we provide new insights in the comprehension of female reproductive cycles and lactation deficiency, thus opening new roads for mothers that cannot breastfeed.

A Comparative Study of Menstrual Hygiene Issues between Public and Private School Going Adolescent Girls in Kathmandu Valley

Introduction: Menstruation is part a of the female reproductive cycle that starts when girls become sexually mature at the time of puberty. During menstrual period, woman bleeds from her uterus via the vagina. Menstruation is generally considered as unclean in our Nepali society. So, good hygienic practices such as the use of sanitary pads and adequate cleaning of the genital areas are essential during menstrual period.
 Material and methods: The comparative study was carried out with adolescent girls studying in public and private schools in Kathmandu valley. A total of 100 adolescent girls, 50 from public school and another 50 from private schools were selected for the study and 25 from each group were taken for quantitative study as well. Two focus group discussions and five key-in-depth interviews were also done to identify the qualitative findings. Ethical approval was taken from NHRC. Quantitative data from the survey was analyzed using SPSS 16.0 software.
 Results: The age of the respondents ranges from 11 to 18 years. The mean age at menarche was 12.37 years in both public and private school adolescent girls. There is a statistically significant difference on the overall score of practice during menstruation between public and private school going adolescent girls.
 Conclusion: Private school adolescent girls were more knowledgeable and maintain menstrual hygiene better as compared to public school adolescent girls.

Flipped Classroom as a Teaching Strategy and Community Health Nursing Student’s Engagement, Satisfaction and Achievement

Menstruation is a uniquely female phenomenon and the most important part of the female reproductive cycle. But painful menstrual pain is a common gynecological complain among women. Many factors play a role and affect the menstrual cycle, which includes hormonal changes, psychological factors, genetic factors and body mass index (BMI). Aim: The current study aimed to assess the relationship between Body Mass Index (BMI) and the severity of menstrual pain and to spotlight on the dietary habits of students and its association with the menstrual profile. Methods: Cross-sectional correctional study design was utilized. 177 agreed to participate in the study selected by stratified cluster sampling technique. A semi-structured self- administered questionnaire was used in data collection. Results: The findings revealed that less than one quarter 14.1 % & 17.5% of the study sample were in the extreme range either underweight or overweight, respectively. 79.1% of the study participants had reported pain during menses and 33.5 % of them describe this pain as severe pain. Furthermore, a statistically significant difference was found between BMI and menstrual profile. Conclusion: It can be concluded that BMI had an effect on the menstrual profile. Therefore, special attention should be given to adolescent's nutrition which leads to maintain the normal BMI and regulate the menstrual cycle. Recommendation: Lifestyle modification and nutritional counseling for female students could alleviate menstrual problems, promoting healthy eating habitats and maintaining an optimal BMI can improve menstrual health. Further research in the nutritional pattern in adolescents can be done especially during the menstrual cycle should be implemented.

Cardiovascular Disease and the Female Disadvantage.

Age-standardised rates of cardiovascular disease (CVD) are substantially higher in men than women. This explains why CVD has traditionally been seen as a “man’s problem”. However, CVD is the leading cause of death in women, worldwide, and is one of the most common causes of disability-adjusted life-years lost. In general, this is under-recognised and, in several ways, women are disadvantaged in terms of CVD. Both in primary and secondary prevention, there is evidence that women are undertreated, compared to men. Women often experience heart disease in a different way compared to men, and lack of recognition of this has been shown to have adverse consequences. Female patients of male cardiac physicians have been found to have worse outcomes than their male counterparts, with no such gender differential for female cardiologists. Clinical trials in CVD primarily recruit male patients, yet, it is well recognised that some drugs act differently in women and men. Diabetes and smoking, and perhaps other risk factors, confer a greater proportional excess cardiovascular risk to women than to men, whilst adverse pregnancies and factors concerned with the female reproductive cycle give women added vulnerability to CVD. However, women’s health research is skewed towards mother and child health, an area where, arguably, the greatest public health gains have already been made, and breast cancer. Hence there is a need to redefine what is meant by “women’s health” to encompass the whole lifecycle, with a stronger emphasis on CVD and other non-communicable diseases. Sex-specific analyses of research data should be the norm, whenever feasible.

Reproductive aspects of the semi-aquatic snake Erythrolamprus miliaris (Dipsadidae: Xenodontini) in the state of Rio de Janeiro, southeastern Brazil.

We analyzed some aspects of reproduction and sexual dimorphism of the semi-aquatic dipsadid snake Erythrolamprus miliaris in the state of Rio de Janeiro, southeastern Brazil. We detected sexual dimorphism in body size (snout-vent length), with females averaging larger than males, but no sexual dimorphism in the relative length of the tail. Oviductal eggs and secondary follicles were found in all seasons, suggesting that female reproductive cycles are continuous, in spite of the tropical seasonal climate in the region. Reproductive males were present throughout the year, suggesting a continuous cycle for males as well. Clutch size averaged 10.3 ± 4.8 (range 4-21) and there was a positive and significant relationship between clutch size and female size. Compared to conspecific populations previously studied in other Atlantic Rainforest areas, populations of E. miliaris from the state of Rio de Janeiro appear more similar overall in their reproductive traits to a more northern population from the state of Bahia than to populations from further south in the states of São Paulo and Paraná.

A study on menstrual disorders among medical students and correlation with BMI

Background: Menstruation is an important part of female reproductive cycle. Menstrual cycle disorders are caused by several factors like hormonal, genetic, psychological, nutritional and organic disorders. The nutritional status is measured by using body mass index. Method: It is a cross sectional study conducted on 205 female medical students in Rangaraya Medical College, Kakinada in January 2020. Data was collected through predesigned questionnaires and measurement of body weight and height and the data was analyzed. Results: out of 205 medical students in the study, regular duration of menstrual cycle is seen in 177(86.34%). polymenorrhea is present in 2(0.97%). Oligomenorrhea is present in 26(12.69%) students. 33 students are overweight and 22 are underweight, normal BMI is present in 150 students. Of these 205 students, only 1 had early menarche at the age of 7 years. Mean age at menarche in the study is 12-13 years. More than 8 days of menstrual flow is seen in 29 students. Heavy flow of menstruation in initial 3 days of cycle is in 1.47% whereas 1.95% had scanty flow. Dysmenorrhea is present in 35% students. Conclusion: In the present study, majority of the subjects are with normal menstruation and most prevalent menstrual abnormality is oligmenorrhea being 12.69%. Furthermore it was concluded from the study that there is no statistical significance between BMI and menstrual irregularities among medical students. Factors other than BMI like stress in the medical profession may be responsible for menstrual irregularities and more studies are necessary in this regard.

Neural correlates of depression in women across the reproductive lifespan - An fMRI review.

Depressive disorders in women emerge largely during transitions in their reproductive aging cycle, which can be attributed to internal endocrine possesses that affect emotion-associated brain circuits. A review was performed to outline the neural basis in depression during female puberty, premenstrual dysphoric disorder (PMDD), postpartum depression disorder (PPD) and perimenopausal depression disorder. For this review, Web of science, Pubmed and PsychInfo databases were searched for functional brain imaging studies addressing reproductive cycle-related mood disorder. The results are summarized and discussed within a broader theoretical framework of major depression disorder (MDD) to determine how reproductive-sensitive phases contribute to affective symptoms and how they relate to the neurobiology of MDD. Neural activation patterns of all depressive disorders related to female reproductive cycle, except for puberty depression, differ from these observed in MDD. While the PMDD results are widely divergent, the activation patterns in PPD show general hypoactivation in all respects. Systematic comparisons between the diverse depression disorders are impeded by the heterogeneous experimental protocols used on different samples, reproductive aging stages and depression types. Given that hormonal fluctuations strongly influence the development of a reproductive cycle-related depression, it is possible that the hormonal and neural patterns are indicative of distinct mood disorder with phase specific biotypes, that only show behavioral similarities to MDD. Understanding the similarities and differences in the neural functioning of female cycle-related mood disorders evaluated against MDD might help elucidate the role of neuroendocrine involvement in development of depression in women, and potentially facilitate the search for prevention and treatment approaches for women' reproductive-related depressions.

Amphibian life history in a temperate environment of the Mexican Plateau: dimorphism, phenology and trophic ecology of a hylid frog, Hyla eximia (=Dryophytes eximius).

The study of demographic and life history aspects of an organism provides valuable information for its conservation. Here, we analyze the phenology of the Mountain Treefrog Hyla eximia (= Dryophytes eximius) in a temperate environment of the Mexican Plateau. Females were larger in snout-vent length and body mass than males. The peak period of activity occurred in the rainy season (May–September), with amplexus and egg deposition occurring between June and July, and larval development from July to August. A logistic model best explained observed male growth patterns, while the Von Bertalanffy model better described female growth. Notably, males grew faster than females, although females reached a larger overall body size. The diet of this species is made up of 10 prey categories. The index of diet importance indicated that males feed mainly on Coleoptera and Diptera, while females feed on Coleoptera, Diptera, Hemiptera, and Aranea. Both females and males showed a significant abundance of plant material in their stomachs, suggesting that H. eximia might exhibit highly specialized feeding behavior. Reproduction was seasonal, and both female and male reproductive cycles are synchronized with the rainy season. These natural history characteristics provide information to better understand their responses to environmental conditions.

Effects of Immobilization Stress on Some Reproductive Functions in Adult Female Albino Rats

AbstractBackground: Various factors can disrupt the female re-productive cycle resulting in subfertility. Reproductive disor-ders and hazards to reproductive health have become prominent public health issue.Aim of Work: Evaluation of the effects of immobilization stress on some reproductive functions in adult female albino rats.Material and Methods: Twenty adult female albino rats of local strain weighing 145-160g were chosen to be the model of the present study. They were divided into two equal groups: Group I (Control group) received no treatment, and Group II (immobilization group) were subjected to immobilization stress for two weeks. Estrus cycle was examined by daily vaginal smear for determination of its phases. Blood samples were withdrawn and serum was separated for determination of FSH, LH, estrogen, progesterone, corticosterone, and prolactin serum levels.Results: Chronic stress was associated with disturbed estrus cycle, gonadotrophic, estrogen, progesterone, corticos-terone, and prolactin hormones. Taken together these distur-bances affect the female reproductive functions.Conclusion: Chronic stress has a drawback effects on the female reproductive functions. So, a great importance must be considered to avoid stressful situation aiming at avoidance of its drawback effects on the body functions.

Changes in Vitellogenic Proteins During The Reproductive Cycle of The Female Tick, Argas persicus

Proteins in the freshly deposited eggs of mated fed female Argas persicus were electrophoretically separated into twelve fractions or egg vitellins (EVts) with Mwt of 24.72-131.45kD. One fraction (131.45kD) existed only in the egg and eleven were exogenous EVts with extraovarian counterparts (vitellogenins) in the hemolymph (HL). Six of them were common EVts (24.72-65.53kD) with similar counterparts in the HL of both male and female and five were female-specific EVts (78.65-112.92 and 48.67kD) with similar counterparts only in the female HL. Eleven vitellogenins (Vgs) and ten exogenous vitellins (Vts) with similar electrophoretic mobilities to EVts were identified in the HL and ovaries, respectively, of mated females. The number and percent amount of the detected vitellogenic protein fractions varied in the different physiological states (10) studied (unfed, 0-7 and 20 day after feeding, daf). Generally, there was an increase of the two parameters in ovary vitellin fractions (with appearance of new Vts) and a decrease in HL vitellogenin fractions during vitellogenesis at the late period of the female reproductive cycle (4-7 and 20 daf). The obtained results support the concept of the uptake of hemolymph Vgs by the ovaries and deposition as Vts in the oocytes during vitellogenesis which may extend till the end of the oviposition period (20 daf) in the female A.persicus.

Experimental Studies on the Reproduction of the Thin-Lipped Mullet, Liza ramada

Like females of many commercially important fishes, Liza ramada fail to complete ovarian development and do not undergo final maturation (FOM), ovulation or spawning when reared in captivity. The aim of the present work was to investigate the histological and physiological changes during the reproductive cycle of Liza ramada reared in freshwater fish ponds and during induction of spawning in saline water. In the present study, the levels of total thyroxine (T4), triiodothyronine (T3) and cortisol in the plasma of Liza ramada in a complete reproductive cycle were measured in correlation with the seasonal histological changes in gonads. During the reproductive cycle of females, serum triiodothyronine (T3), thyroxine (T4) and cortisol decreased during ovarian early-vitellogenesis and increased during mid-vitellogenesis to reach a peak for both T4 and cortisol. Then, these hormones declined to low levels during late-vitellogenesis. At the prespawning stage, all mentioned hormones re-increased to high levels and finally declined during induction of spawning. There was a decrease in serum levels of thyroid and cortisol hormones coincided with an increase in testicular activity of the fish. T3 and T4 increased duringtestis ripening to reach a peak during spawning, while cortisol reached a peak during ripe stage and decreased to low levels during spawning. In conclusion, the seasonal changes in thyroid hormones and cortisol concomitant with gonadal maturation and spawning of Liza ramada support role for these hormones in reproduction and stress response of this fish.

Cryopreservation of Ovarian Tissue: Opportunities Beyond Fertility Preservation and a Positive View Into the Future.

In current years, ovarian tissue cryopreservation (OTC) and transplantation is gaining ground as a successful method of preserving fertility in young women with primarily cancer diseases, hereby giving them a chance of becoming biological mothers later on. However, OTC preserves more than just the reproductive potential; it restores the ovarian endocrine function and thus the entire female reproductive cycle with natural levels of essential hormones. In a female population with an increased prevalence in the loss of ovarian function due to induced primary ovarian insufficiency (POI) and aging, there is now, a need to develop new treatments and provide new opportunities to utilize the enormous surplus of follicles that most females are born with and overcome major health issues associated with the lack of ovarian hormones. Cell/tissue-based hormone replacement therapy (cHRT) by the use of stored ovarian tissue could be one such option comprising both induction of puberty in prepubertal POI girls, treatment of POI and premature menopause, and as primary prevention at the onset of menopause. In the current review, we explore known and entirely new applications for the potential utilization of OTC including cHRT, social freezing, culture of immature oocytes, and a modern ovarian resection for women with polycystic ovaries, and discuss the indications hereof.

Monitoring the reproductive activity in captive bred female ball pythons (P. regius) by ultrasound evaluation and noninvasive analysis of faecal reproductive hormone (progesterone and 17β-estradiol) metabolites trends.

The royal python (Python regius) is commonly bred in captivity. To have a successful breeding season, accurate monitoring of the reproductive activity is necessary. The use of non-invasive monitoring methods in exotics is important in order to minimize stress. For this purpose ultrasound has been anecdotally used to monitor royal python reproductive activity. However, there is limited information regarding the reproductive cycle of this species. The aim of the present study is to monitor the female reproductive cycle of the royal python using ultrasonography and gonadal steroid metabolite measurements in the faeces. The reproductive activity of one hundred twenty-nine adult female P. regius was examined during two consecutive years. We performed brief scans on non-anaesthetized snakes using a portable ultrasound system and a 10–12 MHz linear array transducer (MyLab™ 30 Gold, Esaote). Ultrasound features, dimension and echogenicity of the reproductive structures were determined. During the second reproductive cycle, the hormonal profiles of 30 animals were also evaluated, with a monthly collection of faecal samples. These samples were classified according to reproductive stage, as identified by ultrasonographic examination, and the mean faecal progesterone and 17β-estradiol levels were calculated using the results from an enzyme-linked immunosorbent assay (ELISA). Progesterone levels increased during the reproductive cycle. Estradiol levels showed greater variability, although they appeared to increase before coupling when compared to the levels between coupling and egg laying. The present study suggests that it is possible to identify different phases in the female royal python reproductive cycle: anovulatory phase, transition, folliculogenesis and embryogenesis. Ultrasound is also useful for identifying follicular regression or slugs. Gonadal steroid metabolite measurements from the faeces could help integrate reproductive information. The use of ultrasonography in addition to the steroid metabolite measurement in the faeces gives an accurate picture of ovarian activity in captive adult female royal pythons.

Involvement of the luteinizing hormone surge in the regulation of ovary and oviduct clock gene expression in mice.

Circadian dysfunction perturbs the female reproductive cycle. In particular, mice lacking the clock gene Bmal1 show severe infertility, implying that BMAL1 plays roles in ovulation and luteinization. Here, we examined temporal changes in clock gene expression in the ovary and oviduct before and during gonadotropin-induced follicular growth, ovulation, and luteinization in sexually immature mice. While the oviduct did not show a drastic change in clock gene expression, Bmal1 expression in the ovary was higher than that in control mice during the period from 4 to 16hr after human chorionic gonadotropin (hCG) administration. Bmal1 expression reached a maximum at 16hr after hCG administration, when follicle luteinization occurred. In an interesting manner, administration of hCG to ex vivo-cultured oviduct triggered a shorter circadian period and inevitably resulted in phase advance. Together, our present data suggest that LH surge induces continuous expression of BMAL1 in the mouse ovary and modulates circadian phase in the mouse oviduct.