Ovarian Hormone Secretion Research Articles

Modulation of the Gut Microbiota Structure with Probiotics and Isoflavone Alleviates Metabolic Disorder in Ovariectomized Mice.

The decrease in ovarian hormone secretion that occurs during menopause results in an increase in body weight and adipose tissue mass. Probiotics and soy isoflavones (SIFs) could affect the gut microbiota and exert anti-obesity effects. The objective of this study was to investigate the effects of probiotics and a diet containing SIF (SIF diet) on ovariectomized mice with menopausal obesity, including the gut microbiome. The results demonstrate that Bifidobacterium longum 15M1 can reverse menopausal obesity, whilst the combination of Lactobacillus plantarum 30M5 and a SIF diet was more effective in alleviating menopausal lipid metabolism disorder than either components alone. Probiotics and SIFs play different anti-obesity roles in menopausal mice. Furthermore, 30M5 alters the metabolites of the gut microbiota that increase the circulating estrogen level, upregulates the expression of estrogen receptor α in abdominal adipose tissue and improves the production of short-chain fatty acids (SCFAs). A SIF diet can significantly alter the structure of the fecal bacterial community and enrich the pathways related to SCFAs production. Moreover, 30M5 and a SIF diet acted synergistically to effectively resolve abnormal serum lipid levels in ovariectomized mice, and these effects appear to be associated with regulation of the diversity and structure of the intestinal microbiota to enhance SCFAs production and promote estrogen circulation.

DEHP exposure to lactating mice affects ovarian hormone production and antral follicle development of offspring

Di (2-ethylhexyl) phthalate (DEHP) is widely used as a plastic additive and it could induce reproduction defects and fertility in mammals as environmental endocrine disruptor. However, the effects and potential mechanism of DEHP exposure during lactation stage on follicular development of offspring are still unclear. In this study, we found that the total primordial follicle number and antral follicles in the suckling of mice exposed to DEHP during lactation was significantly reduced. RNA-seq analysis results showed that the transcription levels of genes related to steroid production, ovarian hormone secretion and oxidative stress were significantly changed, which led to a decrease in 17β-estradiol and an increase in oxidative stress. The proportion of DNA damage marker γH2AX in the ovary of female suckling exposed to DEHP was significantly increased. We also found an increase in the level of ovarian apoptosis, and the proliferation of ovarian granulosa cells was inhibited. These alterations also lead to abnormal spindle and chromosome misalignment during oocyte maturation. Overall, our data indicate that lactation exposure to DEHP can affect the secretion of hormones and the development of antral follicles in suckling mice by affecting the secretion pathways of ovarian hormone enzymes and oxidative stress pathway.

LncRNA lnc_13814 promotes the cells apoptosis in granulosa cells of duck by acting as apla-miR-145-4 sponge

ABSTRACT Follicle development is a vital factor which determines the reproductive performance of poultry. Long noncoding RNAs (lncRNAs) have been reported to maintain animal reproductive function and play key roles in ovarian development and hormone secretion. But the regulatory mechanism of lncRNAs in duck follicle development has seldom been reported. In this study, to better explore the molecular mechanism of follicle development in ducks, the follicular lncRNA was sequenced and analyzed. A total of 9,551 lncRNAs were predicted in the duck follicles. Four hundred and forty-five lncRNAs were differentially expressed between the white follicles and yellow follicles. The results of our studies showed that lnc_13814 promoted cell apoptosis in duck GCs. Furthermore, the bioinformatics analysis results demonstrated that lnc_13814 was involved in a lncRNA-miRNA-mRNA coexpression network and it was observed to sponge two follicle-related miRNAs by a luciferase activity assay. Moreover, we found that overexpression of lnc_13814 significantly increased DNA damage inducible transcript 3 (DDIT3) expression and downregulated GCs apoptosis. Finally, we found that lnc_13814 directly binds to and inhibits apla-mir-145-4; then, lnc_13814 increases the expression of DDIT3 and up-regulates GCs apoptosis. Taken together, our findings demonstrate that lncRNAs have potential effects on duck ovarian follicles and lncRNAs may represent a new approach to understand follicular development.

Adiponectin modulates steroid hormone secretion, granulosa cell proliferation and apoptosis via binding its receptors during hens’ high laying period

Adiponectin is an important adipocytokine and plays the roles in multiple metabolic processes via binding its receptors - AdipoR1 and AdipoR2, which has also been found to participate in the regulation of the reproductive system of animals, in particular by influencing the secretion of ovarian steroid hormones. To further investigate the expression of adiponectin and its receptors in follicles after in vitro incubation, and their role in the steroid synthesis of laying hens’ ovaries, we performed qRT-PCR and ELISA to detect the expressions of AdipoQ, AdipoR1, and AidpoR2, and determined the key genes involved in steroidogenesis and the secretion of estradiol (E2) and progesterone (P4) through the in vitro activation of adiponectin (AipoRon) and overexpression or knockdown of AdipoR1 and AdipoR2. Our results revealed that adiponectin and its receptors wildly exist in follicles and granulosa cells, and AdipoRon (5 and 10 µg/mL) had no effect on granulosa cell proliferation and apoptosis but significantly stimulated the secretion of adiponectin and its receptors in granulosa cells after incubation for 24 h. Furthermore, AdipoRon could significantly stimulate the secretion of P4 and inhibit E2 level compared to those of the control group through modulating the key genes expression of steroidogenesis (CYP19A1, StAR, CYP11A1, FSHR, and LHR). The secretion of E2 was also decreased in granulosa cells by the treatments of overexpression and knockdown of AdipoR1/2, however, there was no difference in terms of the level of P4 and StAR expression between them if there was overexpression or knockdown of AdipoR1/2. In addition, it was shown that the secretion of E2 only exhibits a marked drop if co-processing 10 µg/mL AdipoRon and pGMLV AdipoR2 compared to single treatments. Taken together, the study highlighted the role of adiponectin and its receptors in the regulation of steroid synthesis and secretion in ovarian granulosa cells in laying hens.

卵巣ホルモン分泌抑制に関わるα受容体サブタイプとストレス

卵巣ホルモン分泌抑制に関わるα受容体サブタイプとストレス

Administration of a VIP-antagonist in vivo modifies ovarian hormone secretion in a rat model with polycystic ovary syndrome

AimsIn the cyclic rat in estrus, the vasoactive intestinal peptide (VIP) has an impact on ovarian function, which depends on the endocrine status of the animal. In this work, we aimed to clarify the participation of VIP in the pathophysiological condition of polycystic ovary syndrome (PCOS) using a model of PCOS induced by estradiol valerate (EV-PCOS) in rats. Main methodsIn the cyclic rat in estrus and in the EV-PCOS model, we analyzed the acute effects of blocking VIP receptors with the use of an antagonist (Ant-VIP) injected into the left or right ovarian bursa on the steroidogenic response and ovarian catecholamine levels. Key findingsIn the cyclic animal in estrus, the treatment with Ant-VIP in the left ovarian bursa resulted in a reduction in testosterone serum levels and in ovarian levels of dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC), without changes in 4-hydroxy-3-methoxyphenyl (MHPG) and norepinephrine (NE). When the treatment was applied on the right side, only MHPG levels increased.In the EV-PCOS model, the treatment with Ant-VIP in the left ovarian bursa increased testosterone, estradiol, MHPG, and NE levels. When the treatment was performed on the right side, progesterone levels decreased and estradiol increased, without changes in ovarian catecholamines. SignificanceThe binding of VIP to its receptors differentially regulates steroidogenesis in the cyclic animal in estrus and in the EV-PCOS model. The blocking of VIP signaling produces changes in ovarian catecholamines.

Unilateral section of the superior ovarian nerve induces first ovulation in the Zucker fatty (fa/fa) rat

Hyperactivity in the sympathetic nervous system has been shown to be related to the development of ovarian pathologies. In addition, obesity has been found to be associated with multiple reproductive anomalies and is considered a chronic stress condition of low intensity with changes in the peripheral sympathetic activity. Therefore, in the present study, we aimed to evaluate if the information reaching the ovaries through the superior ovarian nerve (SON) modifies the ovarian function of Zucker fatty rats. We performed a unilateral section of the SON at 32 days of age and autopsies were carried out on the day of the first vaginal estrus. The results showed that fatty animals do not ovulate on the day of the first vaginal estrus and exhibit an increase in catecholaminergic fibers and the presence of precystic structures in the ovaries, without changes in the onset of puberty or in the secretion of ovarian and hypophyseal hormones. We also found that the section of the right SON resulted in ovulation on the day of the first vaginal estrus, which was accompanied by a decrease in ovarian noradrenaline content. The section of the left SON caused a delay in puberty without changes in the rest of the parameters. These results provide functional evidence that the peripheral sympathetic innervation participates in the regulation of ovarian functions in an animal model of genetic obesity.

A Preliminary Study on the Characteristics of microRNAs in Ovarian Stroma and Follicles of Chuanzhong Black Goat during Estrus.

microRNAs (miRNAs) play a significant role in ovarian follicular maturity, but miRNA expression patterns in ovarian stroma (OS), large follicles (LF), and small follicles (SF) have been rarely explored. We herein aimed to identify miRNAs, their target genes and signaling pathways, as well as their interaction networks in OS, LF, and SF of Chuanzhong black goats at the estrus phase using small RNA-sequencing. We found that the miRNA expression profiles of LF and SF were more similar than those of OS—32, 16, and 29 differentially expressed miRNAs were identified in OS vs. LF, OS vs. SF, and LF vs. SF, respectively. Analyses of functional enrichment and the miRNA-targeted gene interaction network suggested that miR-182 (SMC3), miR-122 (SGO1), and miR-206 (AURKA) were involved in ovarian organogenesis and hormone secretion by oocyte meiosis. Furthermore, miR-202-5p (EREG) and miR-485-3p (FLT3) were involved in follicular maturation through the MAPK signaling pathway, and miR-2404 (BMP7 and CDKN1C) played a key role in follicular development through the TGF-β signaling pathway and cell cycle; nevertheless, further research is warranted. To our knowledge, this is the first study to investigate miRNA expression patterns in OS, LF, and SF of Chuanzhong black goats during estrus. Our findings provide a theoretical basis to elucidate the role of miRNAs in follicular maturation. These key miRNAs might provide candidate biomarkers for the diagnosis of follicular maturation and will assist in developing new therapeutic targets for female goat infertility.

Food cue-elicited brain potentials change throughout menstrual cycle: Modulation by eating styles, negative affect, and premenstrual complaints

BackgroundWhile there is evidence for increased food intake and craving during the luteal phase, underlying mechanisms are incompletely understood. The present study investigated electrophysiological responses to food pictures as a function of menstrual cycle phase. In addition, the moderating effects of progesterone, eating behaviors (restraint, emotional, orthorexic), negative affect, and premenstrual complaints were explored. MethodsUsing a within-subject design, 35 free-cycling women watched and rated pictures of food (high and low caloric) and control items during the follicular, the ovulatory, and the luteal phase (counterbalanced), while EEG was recorded to examine the late positive potentials (LPP). Salivary gonadal hormones and affect were examined at each occasion. Eating behaviors and premenstrual complaints were assessed once. ResultsFor parietal regions, average LPPs were comparable between cycle phases but slightly larger LPP amplitudes were elicited by high caloric food pictures as compared to the neutral category. Descriptively, both food categories elicited larger parietal LPPs than neutral pictures during the luteal phase. Analyses of LPPs for central-parietal regions showed no effect of picture category or cycle phase, except higher amplitudes in the right area during the luteal phase. During the luteal phase, progesterone and functional interference from premenstrual symptoms (but not age, BMI, picture ratings, affect, estradiol, or eating behaviors) significantly predicted larger parietal LPPs towards high caloric (but not low caloric) pictures. ConclusionOur findings suggest a heightened food cue reactivity during the luteal phase, which may relate to higher ovarian hormone secretion and more functional impact of premenstrual symptoms. This research contributes to a better understanding of menstrual health and the identification of preventive strategies for premenopausal women.

Outcome of laparoscopic uterine artery occlusion for uterine fibroids on ovarian function and complications in patients with uterine fibroid

Objective: The aim of this study is to investigate the outcome of laparoscopic uterine artery occlusion (LUAO) on ovarian function in the treatment of uterine fibroid and its influence on complications.Materials and Methods: A total of 61 patients with uterine fibroid accept LUAO from January 2013 to December 2015 were selected as the research objects. The changes of ovarian hormone secretion volume, internal blood supply of uterine fibroid, uterine volume, fibroid volume, and the occurrence of complications were observed before and 3, 6, 12, and 24 months after surgery. These results were compared with the outcomes of 63 patients with uterine fibroid accept myomectomy.Results: Compared with myomectomy treatment, the length of intraoperative blood loss, operation time, and hospitalization time of patients in the LUAO group were shorter (P < 0.05). Menstruation characteristics, uterine volume, and uterine fibroid volume postoperation were better than the prior ones in the LUAO group (P < 0.05). The ovarian secretion of luteinizing hormone, estradiol, and follicle-stimulating hormone levels in patients in the following 24 months after surgery were not statistically different in two groups (P > 0.05), and the pelvic floor function had similar results.Conclusion: Uterine fibroid treated by LUAO is effective, it can decrease the internal blood supply of uterine fibroid, narrow the volume of uterine fibroid, and little impaction on ovarian function. Hence, this kind of treatment is worthy of promotion.

Comparative analysis of differentially expressed genes between the ovaries from pregnant and nonpregnant goats using RNA-Seq

BackgroundA multitude of genes tightly regulate ovarian follicular development and hormone secretion. These complex and coordinated biological processes are altered during pregnancy. In order to further understand the regulatory role of these genes during pregnancy, it is important to screen the differentially expressed genes (DEGs) in the ovaries of pregnant and nonpregnant mammals. To detect the genes associated with the development of pregnancy in goats, DEGs from the ovaries from pregnant and nonpregnant Anhui white goats (pAWGs and nAWGs, respectively) were analyzed using RNA sequencing technology (RNA-Seq).ResultsIn this study, 13,676,394 and 13,549,560 clean reads were generated from pAWGs and nAWGs, respectively, and 1724 DEGs were identified between the two libraries. Compared with nAWGs, 1033 genes were upregulated and 691 genes were downregulated in pAWGs, including PGR, PRLR, STAR and CYP19A1, which play important roles in goat reproduction. Gene Ontology analysis showed that the DEGs were enriched for 49 functional GO terms. Kyoto Encyclopedia of Genes and Genomes analysis revealed that 397 DEGs were significantly enriched in 13 pathways, including “cell cycle”, “cytokine–cytokine receptor interaction” and “steroid biosynthesis”, suggesting that the genes may be associated with cell cycle regulation, follicular development and hormone secretion to regulate the reproduction process. Additionally, quantitative real-time PCR was used to verify the reliability of the RNA-Seq data.ConclusionsThe data obtained in this work enrich the genetic resources of goat and provide a further understanding of the complex molecular regulatory mechanisms occurring during the development of pregnancy and reproduction in goats. The DEGs screened in this study may play an important role in follicular development and hormone secretion and they would provide scientific basis for related research in the future.

Domestic ruminants as models for the elucidation of the mechanisms controlling ovarian follicle development in humans

It is necessary to understand the basic physiology underlying the complex process of folliculogenesis to address common causes of infertility and to devise innovative strategies to increase the efficiency of assisted reproduction technologies. Availability of suitable ovarian tissue is a major constraint to research in this area in humans, and monovulatory domestic ruminants represent a physiologically relevant model to elucidate basic mechanisms before more focused clinical investigations. This paper reviews the development of several whole animal and cell culture models in ruminants that have allowed basic investigations into the endocrine and local mechanisms regulating preantral and antral follicle development in monovulatory species. Studies on preantral follicle development using the ovarian autograft model have shown, contrary to accepted dogma, that FSH may mediate the rate at which preantral follicles grow and have provided evidence to support the existence of local regulatory feedback mechanisms that influence the rate of primordial follicle initiation and preantral follicle development. Studies on the endocrine control of antral follicle development using the GnRH-antagonist model have shown that a pulsatile mode of LH delivery is not a requirement for normal patterns of follicle development and ovarian hormone secretion. Studies on the local control of somatic cell differentiation using physiological cell culture models have highlighted the essential relationship between somatic cell communication and expression of ditferentiative markers. We conclude that the domestic ruminant represents a valuable model system for the elucidation of the endocrine and local mechanisms controlling both early and terminal stages of follicle development in monovulatory species. The results of these investigations have direct strategic relevance within clinical medicine.

Neural Mechanisms Involved in the Noxious Physical Stress-Induced Inhibition of Ovarian Estradiol Secretion.

Stress is known to change the secretion of ovarian steroid hormones via the hypothalamic-pituitary-ovarian (HPO) axis. Noxious physical stress can cause reflex responses in visceral function via autonomic nerves. This article reviews our recent animal studies on neural mechanisms involved in ovarian estradiol secretion induced by noxious physical stress stimulation. In anesthetized rats, noxious physical stress (pinching the hindpaw or electrical stimulation of the tibial nerve) decreased ovarian estradiol secretion. These noxious stress-induced ovarian hormonal responses were observed after decerebration but were abolished after spinal transection. Electrical stimulation of the ovarian sympathetic nerves (superior ovarian nerves: SON) decreased ovarian estradiol secretion. The reduced secretion of ovarian estradiol induced by hindpaw pinching was abolished by bilateral severance of the SON. Efferent activity of the SON was increased following hindpaw pinching. Thus, the inhibition of ovarian estradiol secretion during noxious physical stress was mainly integrated in the brainstem, and this inhibitory response was due to reflex activation of sympathetic nerves to the ovary. In rats, the sympathetic inhibitory regulation of ovarian estradiol secretion was pronounced when the HPO axis was inhibited by chronic estradiol treatment. Considering the female life cycle, extensive physical stress may inhibit ovarian function, especially before puberty and during old ages when the HPO axis is inactive. Anat Rec, 302:904-911, 2019. © 2019 Wiley Periodicals, Inc.

&lt;b&gt;Reproductive cycles in white Karaman ewes: comparison of ovarian hormone secretion and reproductive behavior in non-pregnant and pregnant ewes in semi-intensive conditions

The objective of this study was to characterize the reproductive cycle both endocrinologically and behaviorally in ewes. Blood samples were analyzed by EIA for progesterone (P 4 ), and RIA for estradiol in order to determine the breeding strategy of non-pregnant (n = 11) and pregnant (n = 9) White Karaman throughout the year in the Middle Anatolia (39.57 0 N, 32.53 0 W), Turkey. Estrous cycle lengths and estrous lengths were 18.36 ± 1.03 days and 35.16 ± 5.95 hours, respectively. The breeding season durations were 283 ± 63.36 days and 229.64 ± 63.74 days according to hormonal and behavioral data respectively (p £ 0.01). The highest and lowest data of estrous occurrence frequency was observed in October and June-July, respectively. P 4 levels ranged from 0.01 to 9.0 ng mL -1 throughout the year and from 0.01 to 0.16 ng mL -1 during anestrous. Mean plasma estradiol levels were 8.42 ± 2.51 pg mL -1 during the estrous cycle. Postpartum anestrous durations were 134.8 ± 18.5 and 120.78 ± 29.89 days (n = 9) according to behavioral observation and hormonal data, respectively. P 4 concentration for the months 1 – 5 of the gestation period ranged from 4.54 to 15.08 ng mL -1 . P 4 concentrations in 4 th and 5 th months of gestation were higher than the other months (p £ 0.01). White Karaman reproductive activity is characterized by an extended breeding season and their relatively insensitivity to photoperiod stimulation allows for efficient out of season lamb production.

Follicular Development and Secretion of Ovarian Hormones during the Juvenile and Adult Reproductive Lives of the Myelin Mutant taiep Rat: An Animal Model of Demyelinating Diseases.

Infertility and reproductive problems have been reported in women with several neurological disorders, for example, demyelination. However, the physiology of such problems has remained unknown so far. The taiep rats are an animal neurological model that initially shows a hypomyelination followed by a progressive demyelination of the central nervous system. This animal has reproductive problems, and the aim of this work is to characterize the follicular development, secretion of ovarian hormones, and presence of noradrenaline in the ovaries of the female taiep rats in the juvenile and adult stages. The taiep rats have low body weight (approximately 19% less than that of SD rats), a delay of 4 days in the age of vaginal opening, and an irregularity in the estrous cycle by the absence or prolongation of some estral cycle stage. In the juvenile stage, we observed a decrease of approximately 44% in the total number of follicles with a 15% increase of atresia and an 80% decrease in the fluorescence intensity of catecholamines in the ovaries, with a 21% increment in plasma concentrations of testosterone. In the adult stage, we observed follicular cysts and a 50% decrease in fluorescence intensity of catecholamines in the ovaries, with changes in the secretion of ovarian hormones, an increase of 20 times in progesterone, and a decrement of a half in estradiol. The demyelination in taiep rats affects follicular development and steroidogenesis in the early stages of the animal's life, and this is maintained until adulthood.

Systematic Analysis of Long Non-Coding RNAs and mRNAs in the Ovaries of Duroc Pigs During Different Follicular Stages Using RNA Sequencing.

The dynamic process involving the selection and maturation of follicles is regulated and controlled by a highly synchronized and exquisitely timed cascade of gene expression. Studies have shown that long non-coding RNA (lncRNA) is essential for the normal maintenance of animal reproductive function and has an important regulatory function in ovarian development and hormone secretion. In this study, a total of 2076 lncRNAs (1362 known lncRNAs and 714 new lncRNAs) and 25,491 mRNAs were identified in libraries constructed from Duroc ovaries on days 0, 2 and 4 of follicle development. lncRNAs were shorter, had fewer exons, exhibited a shorter ORF (Open Reading Frame) length and lower expression levels, and were less conserved than mRNAs. Furthermore, 1694 transcripts (140 lncRNAs and 1554 mRNAs) were found to be differentially expressed in pairwise comparisons. A total of 6945 co-localized mRNAs were detected in cis in 2076 lncRNAs. The most enriched GO (Gene Ontology) terms were related to developmental processes. KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis revealed that the differentially expressed lncRNAs targeted mRNAs, and the differentially expressed mRNAs were related to the TGF-β signaling pathway, the PI3K-Akt signaling pathway, the Retinol metabolic pathway and the Wnt signaling pathway. This study deepened our understanding of the genetic basis and molecular mechanisms of follicular development in pigs.

Response Of Muscle Damage Markers After Acute Heavy Exercise In Different Ovarian Hormone Secretion

PURPOSE To evaluate the response of muscle damage markers to acute heavy resistance exercise in female athletes with different ovarian hormone levels. METHODS Eleven female college athletes were enrolled. They were divided into 2 groups according to the variations in their ovarian hormone levels: the ovarian-suppression group (OVS) and the cyclic menstruation group (CYC). Measurements were taken under 2 conditions (rest and exercise) over a 3-week period. Measurements in CYC were started after the start of menstruation (week 1). The exercise involved 6 sets of 5 squats at 90% 1-RM with a 3-min rest between each set. During rest, the athletes remained quiet and sat for 30 min. Blood chemicals including serum creatine kinase (CK) and lactate dehydrogenase (LD), Profile of Mood State 2 (POMS2) TMD scores, and muscle soreness evaluated using the 100-mm Visual Analog Scale were measured before, immediately after, 30 min after, 60 min after, and 24 h after each condition. RESULTS In CYC, week-2 estradiol (E2) levels during exercise were significantly higher than those of weeks 1 and 3 (336.7±104.6 vs 69.5±44.2 and 109.8±28.7 pg/mL). During rest, week-1 E2 levels were significantly lower than those of weeks 2 and 3 (63.2±36.9 vs 116.2±18.1 and 198.8±19.7 pg/mL). In OVS, E2 levels did not differ significantly at any point in the study (weeks 1, 2, and 3: 45±12.1, 66.2±8.8, 59.8±14.2 pg/mL during exercise and 52.2±23.2, 52.0±18.1, 43.0±20.1 pg/mL during rest). CK was significantly higher in week 2 in OVS than in CYC before both conditions (163±12.1 vs 196.1±11.0, 158.4±10.4 vs 201.3±11.4 U/L). LD and TMD scores were significantly higher in OVS than in CYC during rest and before exercise. CK in CYC increased significantly immediately after exercise when compared with its level before exercise in week 1 (178.3±12.8 vs 218.2±39.7 U/L) and 3 (189.7±8.1 vs 207.0±7.6 U/L). CK in OVS significantly increased immediately and 30 min after exercise when compared with its level before exercise in every week (week 1: before exercise 191.1±114.0 vs immediately after 256.4±11.2 vs 30 min after 239.4±11.5; week 2: 196.3±11.0 vs 244.0±8.1 vs 239.4±13.1; week 3: 199.9±8.8 vs 240.6±5.4 vs 234.0±4.9 U/L). CONCLUSION Ovarian suppression in athletes may lead to severer muscle damage because of lack of muscle protection by estradiol.

Ovarian steroid hormone secretion activity examined after supplementation of green tea extract.

This study aimed at examining the secretion activity of steroid hormones progesterone and 17beta-estradiol by porcine ovarian granulosa cells after addition of green tea extract. Granulosa cells were incubated with green tea extract (at doses of 0.01, 0.1, 1, 10 and 100 microg.ml(-1). Another set of cells were incubated with green tea extract at the above doses along with additional supplementation of follicle stimulating hormone (FSH) at 10 microg.ml(-1). Release of hormones by granulosa cells was assessed by EIA after 24 h exposure. Secretion of steroid hormones was not affected either by green tea extract alone or after FSH supplementation with green tea extract. Results indicate that ovarian steroidogenesis is not affected by green tea under conditions used in the experiment.

MiR-26a-5p Regulates TNRC6A Expression and Facilitates Theca Cell Proliferation in Chicken Ovarian Follicles

Ovarian theca cells play an indispensable role in ovarian follicular development and hormone secretion. miR-26a-5p was reported to be differentially expressed in mature and immature chicken ovaries in our previous study; however, the role of miR-26a-5p in regulating ovarian follicle function is still unclear. In this study, we demonstrated that the expression dynamics of TNRC6A mRNA in either chicken ovaries or follicles showed an opposite trend compared with that of chicken miR-26a-5p expression. miR-26a-5p inhibited TNRC6A mRNA expression by directly targeting its 3'-untranslated region in cultured chicken theca cells. Overexpression of miR-26a-5p promoted chicken follicular theca cell proliferation in vitro. Furthermore, overexpression of miR-26a-5p and knockdown of TNRC6A significantly upregulated the antiapoptotic BCL-2 gene. Taken together, this study revealed the expression dynamics of miR-26a-5p and TNRC6A in chicken ovaries and ovarian follicles and the relationship between the expression of miR-26a-5p and TNRC6A in chicken ovarian theca cells. These results suggest that miR-26a-5p facilitates chicken ovarian theca cell proliferation by targeting the TNRC6A gene.

Doxorubicin Has Dose-Dependent Toxicity on Mouse Ovarian Follicle Development, Hormone Secretion, and Oocyte Maturation.

Doxorubicin (DOX), one of the most commonly used anticancer medications, has been reported to affect fertility by damaging ovarian follicles; however, the dose-dependent toxicity of DOX on the dynamic follicle development and oocyte maturation has not been well-defined. Our objective is to determine the effects of human-relevant exposure levels of DOX on follicular functions across developmental time. In vitro cultured multilayered secondary mouse follicles were treated with DOX at 0, 2, 20, 100, and 200 nM for 24 h, and follicle development, hormone secretion, and oocyte maturation were analyzed. DOX caused dose-dependent toxicity on follicle growth, survival, and secretion of 17β-estradiol (E2). At 200 nM, DOX induced DNA damage and apoptosis in follicle somatic cells first and then in oocytes, which was correlated with the uptake of DOX first to the somatic cells followed by germ cells. Follicles treated with DOX at 0, 2, and 20 nM showed similar oocyte metaphase II (MII) percentages after in vitro oocyte maturation; however, 20 nM DOX significantly increased the number of MII oocytes with abnormal spindle morphology and chromosome misalignment. In an effort to harmonize the in vitro study to in vivo treatment, dose-dependent toxicity on oocyte meiotic maturation was found in 16-day-old CD-1 mice treated with DOX at 0, 0.4, 2, and 10 mg/kg, consistent with the in vitro oocyte maturation outcomes. Our study demonstrates that DOX has dose-dependent toxicity on ovarian follicle development, hormone secretion, and oocyte maturation, which are three key factors to support the female reproductive and endocrine functions.