Effect of different culture systems and 3, 5, 3'-triiodothyronine/follicle-stimulating hormone on preantral follicle development in mice

Associations between a normal-range free thyroxine concentration and ovarian reserve in infertile women undergoing treatment via assisted reproductive technology

BACKGROUND

Some recent studies have shown that female subclinical hypothyroidism (SCH) is associated with diminished ovarian reserve (DOR). In this study, we aimed to investigate whether serum-free thyroxine (fT4) concentrations within the reference range are associated with ovarian reserve in women.

METHODS

This cross-sectional study included 4933 infertile women with normal-range fT4 concentrations who received assisted reproductive technology treatment in our clinic. The data of women in different fT4 concentration tertiles (namely 12-15.33, 15.34-18.67, and 18.68-22 pmol/L) were compared with ovarian reserve markers, namely the anti-Müllerian hormone (AMH) concentration, the antral follicle count (AFC), and the number of aspirated oocytes. The primary outcomes were the AMH concentration and the risk of DOR, diagnosed as an AMH concentration < 1.1 ng/mL.

RESULTS

The average ages of women in the low-normal, middle-normal, and high-normal fT4 tertiles were 33.20 (standard deviation [SD]: 5.11), 32.33 (SD: 5.13), and 31.61 (SD: 5.10) years, respectively (p < 0.0001). AMH concentrations (adjusted mean: 3.32 [95% confidence interval {CI}: 3.16 to 3.50] vs. 3.51 [3.40 to 3.62] vs. 3.64 [3.50 to 3.80] ng/mL, p = 0.022) were significantly different between the fT4 concentration tertiles. The risk of DOR was significantly increased in the low-normal (adjusted odds ratio: 1.61 [95% CI: 1.01 to 2.58]) and middle-normal (1.47 [95% CI: 1.00 to 2.16]) tertiles compared with the high-normal tertile. Subgroup analysis showed that AMH concentrations were significantly different among the fT4 concentration tertiles in women aged < 35 years (adjusted mean: 3.94 [95% CI: 3.70 to 4.20] vs. 4.25 [4.11 to 4.39] vs. 4.38 [4.18 to 4.58], p = 0.028), whereas this difference was not significant in women aged ≥ 35 years (p = 0.534). The general additive models using fT4 as a continuous variable indicated that a lower fT4 concentration within the normal range was significantly associated with a lower AMH concentration (p = 0.027), a lower AFC (p = 0.018), a lower number of aspirated oocytes (p = 0.001), and a higher risk of DOR (p = 0.007).

CONCLUSION

Low-normal fT4 concentrations are associated with lower ovarian reserve in infertile women.

The effects and mechanism of taxanes on chemotherapy-associated ovarian damage: A review of current evidence

Chemotherapy is often a cause of premature ovarian insufficiency and infertility since the ovarian follicles are extremely sensitive to the effects of chemotherapeutic agents. Different chemotherapeutic agents with varying mechanisms of action may damage ovarian function differently. Taxanes are widely used in clinical cancer treatment, but the specific reproductive toxicological information is still controversial. This review described the impact and duration of taxanes on ovarian function in women and analyzed the possible reasons for different conclusions. Furthermore, the toxicity of taxanes on ovarian function and its possible mechanisms were discussed. The potential protective strategies and agents against ovarian damage induced by taxanes are also reviewed.

Mechanisms of OCT4 on 3,5,3'-Tri-iodothyronine and FSH-induced Granulosa Cell Development in Female Mice

Octamer-binding transcription factor 4 (OCT4) regulates the pluripotency of stem cells and also plays important roles in granulosa cells growth, which is regulated by follicle-stimulating hormone (FSH). Thyroid hormone (TH) is important for the development and maturation of follicles and the maintenance of various endocrine functions. Although 3,5,3'-triiodothyronine (T3) enhances the effects of FSH on the regulation of the growth of granulosa cells and development of follicles, it is unclear whether and, if so, how TH combines with FSH to regulate OCT4 expression in granulosa cells during the preantral to early antral transition stage. Our results showed that T3 enhanced FSH-induced OCT4 expression. However, T3/FSH-induced cellular growth was reduced by OCT4 small interfering RNA. OCT4 knockdown significantly increased the number of apoptotic cell. Moreover, T3 combined with FSH to increase estrogen receptor β (ERβ) expression but did not significantly affect estrogen receptor α expression. ERβ knockdown dramatically decreased T3/FSH-induced OCT4 expression and cell development and increased cell apoptosis. The phosphoinositide 3-kinases/protein kinase B pathway was involved in hormones inducing OCT4 and ERβ expressions. Furthermore, the hormones regulating OCT4 and ERβ expressions were regulated by cytochrome P450 lanosterol 14a-demethylase (CYP51), a key enzyme in sterol and steroid biosynthesis. T3 and FSH cotreatment potentiated cellular development by upregulating OCT4 expression, which is mediated by CYP51 and ERβ. These regulatory processes are mediated by the phosphoinositide 3-kinase/protein kinase B signaling pathway. These findings suggest that OCT4 mediates the T3 and FSH-induced development of follicles.

The relationship between thyroid function and ovarian reserve: a prospective cross-sectional study

Background

Thyroid dysfunction can affect fertility and miscarriage risk by affecting the process of follicular growth, embryo development, implantation, and placental formation. It has been suggested that thyroid disorders are associated with ovarian reserve by affecting the follicular process. The aim of the present study was to investigate the relationship between thyroid hormone levels and ovarian reserve.

Methods

Three hundred fourteen women with infertility due to various etiologies were enrolled in this study (172 individuals with Anti-Mullerian hormone (AMH) level ≥ 1.1 ng/ml and 142 individuals with AMH < 1.1 ng/ml). Serum levels of follicle-stimulating hormone (FSH), estradiol (E2) on day 2–4 of menstrual cycles, AMH, Thyroid-stimulating hormone (TSH), and thyroxine (free T4) were evaluated.

Results

In participants with age over 35 years, median TSH level in women with AMH < 1.1 ng/ml was significantly higher than those with AMH ≥1.1 ng/ml (P-value =0.037). There was no significant difference in body mass index (BMI) in patients with age older than 35 years and younger than 35 years sub-groups based on AMH level (P-value = 0.102, and P-value = 0.909 respectively). With one unit increase in TSH level, the odds of having AMH < 1.1 ng/ml increases by 1.25 times or by 25% (P-value =0.017). Receiver operator characteristic (ROC) curve analysis showed a TSH cut-off point of 1.465 mIU/L in participants over 35 years in identifying decreased AMH level.

Conclusion

Our study supports the relationship between TSH level and ovarian reserve so that with an increase in TSH from a certain level is associated with a decrease in ovarian function.

Effect of animal-sourced bioactive peptides on the in vitro development of mouse preantral follicles

The aim of this study was to investigate the effect of bioactive peptides (BAPT) from animal sources on the development of mouse preantral follicles in vitro. Preantral follicles were isolated and randomly divided into the following groups: an untreated group (control) and three groups supplemented with 20, 40 and 60 μg/mL BAPT, respectively. After establishing the in vitro follicle culture, the gene expression levels and hormone levels were quantified. After in vitro maturation, the developmental rates, reactive oxygen species (ROS) production levels and mitochondrial distributions of MII oocytes were investigated, followed by the analyses of embryonic developmental rates after in vitro fertilization.The results showed that BAPT promoted the growth of mouse preantral follicles. Notably, after 14 d of in vitro culture, the levels of 17 β-estradiol and progesterone were up-regulated with BAPT treatments. Moreover, the expression levels of Oct4, Bmp15, GDF9, FOXO3, Zp3, FOXL2, Inhibin alpha, SOD2, Catalase, GPx and Bcl-2 in the developing follicles were significantly up-regulated after BAPT treatments (P < 0.05), while BAPT significantly inhibited the expression levels of BAX (P < 0.05). Following BAPT treatments, the ROS production levels of MII oocytes were decreased while the mitochondrial distributions were significantly enhanced. Furthermore, increased maturation rates, fertilization and embryonic developmental rates were found in these BAPT-treated groups (P < 0.05).These results demonstrated that BAPT significantly improved the development of preantral follicles in vitro by reducing ROS-dependent cellular damages and by enhancing mitochondrial distributions, thereby promoting the further applications of animal-derived BAPT in biomedical research.

Thyroid hormones T3 and T4 regulate human luteinized granulosa cells, counteracting apoptosis and promoting cell survival

PURPOSE

Fine and balanced regulation of cell proliferation and apoptosis are key to achieve ovarian follicle development from the primordial to the preovulatory stage and therefore assure female reproductive function. While gonadotropins are the major and most recognized regulators of follicle cell growth and function, other factors, both systemic and local, play equally important roles. This work is aimed at evaluating the effects of thyroid hormones (THs) on human granulosa luteinized (hGL) viability.

METHODS

Human GL cells derived from assisted reproduction treatments were exposed to T3 or T4. Cell viability was evaluated by MTT assay. Apoptosis was evaluated by the TUNEL assay and active caspase-3 staining. StAR, CYP19A1,Caspase-3, P53 and BAX mRNA were evaluated by real-time PCR. LC3-I/-II, AKT and pAKT were evaluated by western blot.

RESULTS

T3 and T4 promoted cell viability in a dose-dependent modality and modulate StAR and CYP19A1 expression. T3 and to a lesser extent T4 mitigated cell death induced by serum starvation by inhibition of caspase-3 activity and expression of P53 and BAX; and attenuate cell death experimentally induced by C2-ceramide. Cell death derived from starvation appeared to be involved in autophagic processes, as the levels of autophagic markers (LC3-II/LC3-I ratio) decreased when starved cells were exposed to T3 and T4. This effect was associated with an increase in pAkt levels.

CONCLUSION

From the present study, THs emerge as potent anti-apoptotic agents in hGL cells. This effect is achieved by inhibiting the apoptosis signalling pathway of BAX and caspase-3, while maintaining active the PI3K/AKT pathway.

Thyroid Hormones and Functional Ovarian Reserve: Systemic vs. Peripheral Dysfunctions

Thyroid hormones (THs) exert pleiotropic effects in different mammalian organs, including gonads. Genetic and non-genetic factors, such as ageing and environmental stressors (e.g., low-iodine intake, exposure to endocrine disruptors, etc.), can alter T4/T3 synthesis by the thyroid. In any case, peripheral T3, controlled by tissue-specific enzymes (deiodinases), receptors and transporters, ensures organ homeostasis. Conflicting reports suggest that both hypothyroidism and hyperthyroidism, assessed by mean of circulating T4, T3 and Thyroid-Stimulating Hormone (TSH), could affect the functionality of the ovarian reserve determining infertility. The relationship between ovarian T3 level and functional ovarian reserve (FOR) is poorly understood despite that the modifications of local T3 metabolism and signalling have been associated with dysfunctions of several organs. Here, we will summarize the current knowledge on the role of TH signalling and its crosstalk with other pathways in controlling the physiological and premature ovarian ageing and, finally, in preserving FOR. We will consider separately the reports describing the effects of circulating and local THs on the ovarian health to elucidate their role in ovarian dysfunctions.

Subclinical Hypothyroidism Is Associated with Lower Ovarian Reserve in Women Aged 35 Years or Older

Background: Overt thyroid diseases have been identified as risk factors for female infertility. However, it remains largely unclear whether subclinical hypothyroidism (SCH), a very common thyroid disorder, is associated with female infertility. This study aimed to investigate the potential association between SCH and the ovarian reserve in women seeking infertility treatment. Methods: This retrospective study included 2568 women with normal thyroid function (n = 2279) or SCH (n = 289) who visited our clinic for infertility treatment. Ovarian reserve markers, including follicle-stimulating hormone (FSH) concentrations on days 2-4, the antral follicle count (AFC), and anti-Müllerian hormone (AMH) concentration, were compared between euthyroid women and those with SCH. Multiple linear and Poisson regression analyses were used to estimate the associations of SCH with ovarian reserve markers. These analyses were repeated separately in women aged <35 (n = 1349) and ≥35 years (n = 1219). Results: In the total study population, women with SCH had significantly lower AMH concentrations (median: 2.05 vs. 2.51 ng/mL, p = 0.015) and AFCs (median: 10.0 vs. 11.0, p = 0.013), compared with euthyroid women. In linear and Poisson regression analyses, SCH was significantly associated with a higher basal FSH concentration (mean difference = 1.13 mIU/mL [95% confidence interval (CI) 0.97 to 1.29 mIU/mL], p < 0.001), lower AMH concentration (mean difference = -0.27 ng/mL [CI -0.43 to -0.12 ng/mL], p = 0.001), and lower AFC (mean difference = -0.7 [CI -1.3 to -0.2], p = 0.005). In women aged ≥35 years, SCH was significantly associated with FSH (mean difference = 1.74 mIU/mL, p < 0.001) and AMH concentrations (mean difference = -0.40 mg/mL, p < 0.001) and AFC (mean difference = -0.8, p < 0.001). In women <35 years old, SCH was significantly associated with a higher FSH concentration (mean difference = 0.30 mIU/mL, p < 0.001), but not with AMH or AFC concentrations (p = 0.84 and 0.06, respectively). Thyroperoxidase antibody (TPOAb) positivity was not associated with measures of ovarian reserve. Conclusions: The data suggest that SCH is associated with decreased ovarian reserve during later reproductive age. TPOAb positivity was not associated with ovarian reserve. Future research is necessary to investigate the underlying molecular mechanisms regulating the diminished ovarian reserve in women with SCH and to evaluate whether levothyroxine supplementation may improve the ovarian function of women with SCH.

Regulation by 3,5,3'-tri-iodothyronine and FSH of cytochrome P450 family 19 (CYP19) expression in mouse granulosa cells

Cytochrome P450 family 19 (CYP19) plays an important role in follicular development, which is regulated by FSH. Although 3,5,3'-tri-iodothyronine (T3) combines with FSH to induce preantral follicle growth and granulosa cell development, the mechanism involved remains unclear. The aim of the present study was to determine the cellular and molecular mechanisms by which thyroid hormone (TH) and FSH regulate CYP19 expression and sterol biosynthesis during preantral follicle growth. Mice were injected subcutaneously (s.c.) with eCG (Equine chorionic gonadotropin). The results showed that eCG increased CYP19 expression in ovarian cells. CYP19 expression in granulosa cells was increased after FSH treatment, and this response was enhanced by T3. Knockdown of CYP19 significantly decreased granulosa cell viability and hormone-stimulated proliferation. In addition, CYP19 knockdown also blocked T3- and FSH-induced oestradiol (E2) synthesis in granulosa cells. Furthermore, activation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway was required for T3 and FSH regulation of CYP19 expression. In conclusion, the results of the present study indicate that CYP19 is important for T3- and FSH-induced granulosa cell development in the early stages. CYP19 could be a downstream effector of the PI3K/Akt pathway in regulating TH and FSH during follicular development and sterol biosynthesis. The findings suggest that CYP19 is a novel mediator of T3- and FSH-induced follicular development.

Thyroid hormones act as mitogenic and pro survival factors in rat ovarian follicles

PURPOSE

Thyroid disorders are clinically associated with impaired fertility in women, and these abnormalities can be improved by restoring the euthyroid state. The exact mechanisms of thyroid effect on female fertility are not well known; however, it is conceivable that thyroid hormones (THs) might act on ovarian physiology via receptors in granulosa cells. This work is aimed at evaluating the effects of THs on non-tumoral granulosa cells and follicles.

METHODS

Freshly isolated rat ovarian follicles and granulosa cells were exposed to T3 or T4 (THs). Cell growth and viability were evaluated by cell counting and the MTT assay, respectively, follicle growth was evaluated by volume measurements. Apoptosis was evaluated by the TUNEL assay and active Caspase 3 staining. rGROV cells were exposed to T3, and apoptosis was induced by serum deprivation. Bcl2, Bcl-2-associated X protein (BAX), Akt and pAkt expression were evaluated by western blot.

RESULTS

T3 induced a 40% increase in follicle volume (after 7 days). This increase was presumably due to the observed decrease (33%) in the apoptotic rate of the granulosa cell population. Both T3 and T4 caused a dose-dependent increase in rat granulosa cell number and viability. In addition, THs decreased the cell apoptotic rate in a dose-dependent manner. In both conditions, T3 appeared to be more efficient. In rGROV cells, 100 nM T3 induced cell growth and, in the absence of growth factors, reduced cell apoptosis by 40%, downregulating Caspase 3 and BAX. This effect was associated with an increase in pAkt levels. The involvement of the PI3 K pathway was confirmed by the ability of the PI3 K specific inhibitor (LY-294,002) to abolish T3 pro-survival action.

CONCLUSIONS

THs influence cell survival of ovarian granulosa cells. This effect likely contributes to the TH-induced follicle volume increase.

Panax ginseng Extract Improves Follicular Development after Mouse Preantral Follicle 3D Culture

Objective

Panax ginseng is a popular traditional herb that has been used in complementary and alternative medicine in eastern Asia, and it possesses pharmacologically active compounds like ginsenosides (GSs). This study aimed to investigate the impact of Panax ginseng extract (PGE) at different concentrations on in vitro follicular function and development in a three-dimensional (3D) culture system fabricated using sodium alginate after 12 days of culture.

Materials and Methods

In this experimental study, preantral follicles (n=661) were mechanically isolated from the ovaries of 14-day-old female NMRI mice using 29-gauge insulin syringes. Follicles were individually capsulated within sodium alginate, and divided into four groups including control and experimental groups 1, 2, and 3. Then, they were cultured for 12 days in the medium supplemented with different concentrations of PGE (0, 50, 100, and 500 µg/ mL, for control groups and groups 1, 2 and 3, respectively). At the end of the culture period, the mean diameter and maturation of follicles, follicular steroid production, mRNA expression level of proliferating cell nuclear antigen (PCNA) and follicle stimulating hormone receptor (FSH-R), and reactive oxygen species (ROS) levels in collected metaphase-II (MII) oocytes were determined.

Results

The mean diameter of follicles in group 2 was significantly increased as compared to other groups (P<0.001). The percentages of the survival and maturation rate and levels of secreted hormones were higher in group 2 than the other groups (P<0.05). Follicles cultured in the presence of PGE 100 µg/mL had higher levels of proliferation cell nuclear antigen (PCNA) and follicle stimulating hormone receptor (FSH-R) mRNA expression in comparison to other groups (P<0.05). Moreover, oocytes collected from groups 2 and 3 had lower levels of ROS as compared to other groups (P<0.05).

Conclusion

Our results suggest that PGE at the concentration of 100 µg/mL induces higher follicular function and development in the 3D culture system.

Role of OCT4 in the Regulation of FSH-Induced Granulosa Cells Growth in Female Mice

As a member of the POU (Pit-Oct-Unc) transcription factor family, OCT4 (Octamer-binding transcription factor 4) is associated with the cellular proliferative. However, the roles of OCT4 in regulating the transition from preantral follicle to early antral follicle are still remains unclear. To evaluate the effect of OCT4 on cellular development in ovary, mice were injected with eCG in vivo or granulosa cells were co-cultured with FSH in vitro. The results showed that eCG up-regulated ovarian OCT4 expression. Meanwhile, OCT4 expression in granulosa cells was also up-regulated by FSH, and knockdown of OCT4 by siRNA significantly decreased FSH-induced cellular viability. Moreover, gonadotropin increased p-GSK3β (Glycogen synthase kinase 3-beta) level, β-catenin expression and its translocation to nuclear in ovarian cells. In addition, the inhibition of GSK3β activity by CT99021 significantly increased the expression of β-catenin and OCT4 in granulosa cells. And knockdown β-catenin by siRNA dramatically abolished FSH-induced OCT4 expression and cellular development. Furthermore, FSH-induced the phosphorylation of GSK3β, expression of β-catenin and OCT4, and translocation of β-catenin were mediated by the PI3K/Akt pathway. Taken together, the present study demonstrates that FSH regulated OCT4 expression via GSK3β/β-catenin pathway, which was mediated by the PI3K/Akt pathway. And these regulations are involved in ovarian cell development.

Mitochondrial Protein Turnover Is Critical for Granulosa Cell Proliferation and Differentiation in Antral Follicles

Granulosa cell (GC) proliferation is essential for follicular development. FSH is a key factor in GC proliferation, and a continuous supply of high levels of ATP is necessary for cell proliferation. However, genes encoding proteins of the glycolytic pathways are poorly expressed in GCs. Therefore, we hypothesized that mitochondrial gene expression and protein synthesis play a primary role in ATP production during GC proliferation. To test this hypothesis, we performed an in vivo study of GCs collected from 23-day-old mice ovaries with or without equine chorionic gonadotropin (eCG) priming. It was observed that mitochondrial activity with membrane potential, expression of protein-coding genes (Nd1-6, Cytb, Atpase6,8) and transcription-related genes (Polrmt, Tfam, Tfb2m), copy number of mitochondrial (mt-)DNA, and protein synthesis were increased in GCs after 24 hours of eCG injection and mostly maintained elevated up to 48 hours. Therefore, we performed in vitro culture of GCs in DMEM medium supplemented with FSH, testosterone, and serum and containing different glucose concentrations with or without d-chloramphenicol (CRP) for 24 hours. GC proliferation and ATP production were observed to be independent of glucose concentration. Furthermore, FSH-induced mitochondrial activity with membrane potential, ATP content, BrdU-incorporated cell proliferation, intensity of mt-ND1 and mt-ND6 proteins, and expressions of marker genes for proliferation and differentiation were significantly decreased by CRP treatment. These results revealed the crucial role of mitochondria in the supply of ATP and the necessity of mitochondrial gene expression and protein synthesis in not only the proliferation but also the differentiation of GCs during follicular development.

Association of Thyroid Function and Autoimmunity with Ovarian Reserve in Women Seeking Infertility Care

BACKGROUND

While overt thyroid disease is a well known risk factor for infertility, the potential consequences of mild thyroid dysfunction or thyroid autoimmunity remain unknown. Experimental studies suggest a considerable role for thyroid hormone in the physiological mechanisms of ovarian reserve, but translation of such findings to human studies remains rare. A potential role for thyroid function in female reproduction could be especially relevant when the cause of infertility remains unknown, such as in women with diminished ovarian reserve (DOR) or unexplained infertility. The aims of this study were to investigate the association of thyroid function and autoimmunity with markers of ovarian reserve day 3 follicle-stimulating hormone (FSH) concentrations and antral follicle count (AFC), and to investigate whether thyroid function or autoimmunity may have different effects in women with DOR or unexplained infertility.

METHODS

Thyrotropin, free thyroxine, thyroxine, free triiodothyronine (fT3), triiodothyronine, thyroid peroxidase antibodies (TPOAbs), and thyroglobulin antibodies (TgAbs), as well as AFC and the day 3 FSH concentration, were measured among women seeking fertility treatment at the Massachusetts General Hospital Fertility Center. Multiple linear or mixed regression models were used to study the association of thyroid function or autoimmunity with AFC or day 3 FSH.

RESULTS

In the total study population (436 women, 530 AFC measurements), there was no association of thyroid function or TPOAb positivity with AFC. However, TgAb positivity was associated with a higher AFC (mean difference = 3.4 [95% confidence interval (CI) 1.8-5.1], p < 0.001). In women with DOR or unexplained infertility, lower fT3 and TPOAb positivity were associated with a lower AFC (fT3: continuous nonlinear association, p = 0.009; TPOAb positivity: -2.3 follicles [confidence interval -3.8 to -0.5], p = 0.01), while TgAb positivity was not associated with AFC. Neither thyroid function nor thyroid antibody positivity was associated with the day 3 FSH concentration.

CONCLUSIONS

This study found that lower fT3 and TPOAb positivity are associated with a lower AFC in women with DOR or unexplained infertility. Future studies are required to replicate these findings and further elucidate the role of TgAbs and underlying mechanisms through which thyroid function and autoimmunity is associated with ovarian reserve.

Levothyroxine supplementation improves serum anti-Müllerian hormone levels in infertile patients with Hashimoto's thyroiditis

AIM

Thyroid dysfunction and autoimmunity are associated with an adverse effect on fertility. An aberrant high thyroid stimulating hormone level is associated with diminished ovarian reserve in women of reproductive age; however, the utility of levothyroxine (LT4) replacement for infertile patients with subclinical hypothyroidism is still under discussion. The aim of this study was to investigate whether LT4 supplementation for infertile patients with subclinical hypothyroidism improves impaired ovarian function.

METHODS

We measured levels of serum thyroid-related hormones and a biomarker of ovarian function, anti-Müllerian hormone (AMH) in infertile women from 2014 to 2015. Out of a consecutive 1431 infertile patients, 311 patients with an elevated thyroid stimulating hormone level (≥ 2.5 μIU/mL) underwent detailed thyroid examinations, including blood tests of thyroid antibodies. We recruited 174 infertile patients, excluding patients with factors impacting ovarian and thyroid function. We evaluated alterations in AMH and thyroid related hormone levels during LT4 supplementation and infertility treatment with assisted reproductive technology.

RESULTS

After LT4 supplementation, no significant change in the average AMH level was detected overall. However, the AMH level in 35 patients with Hashimoto's disease increased significantly after treatment (1 month 1.3 ± 0.5 fold, P = 0.007; 3 months 1.3 ± 0.4 fold, P = 0.040). The AMH level in patients with thyroglobulin antibody-positive and thyroid peroxidase antibody-negative also significantly increased after LT4 treatment (1 and 3 months 1.5 fold; P = 0.023).

CONCLUSION

In the patients with Hashimoto's disease, preconception LT4 treatment may relieve adverse effects, including autoimmune antibodies, and support follicular development.

Role of CYP51 in the Regulation of T3 and FSH-Induced Steroidogenesis in Female Mice

Cytochrome P450 lanosterol 14α-demethylase (CYP51) is a key enzyme in sterol and steroid biosynthesis that is involved in folliculogenesis and oocyte maturation, which is regulated by follicle-stimulating hormone (FSH), as a key reproductive hormone during follicular development. Thyroid hormone (TH) is also important for normal reproductive function. Although 3,5,3'-triiodothyronine (T3) enhances FSH-induced preantral follicle growth, whether and how TH combines with FSH to regulate CYP51 expression during the preantral to early antral transition stage is unclear. The objective of this study was to determine the cellular and molecular mechanisms by which T3 and FSH regulate CYP51 expression and steroid biosynthesis during preantral follicle growth. Our results indicated that CYP51 expression was upregulated in granulosa cells by FSH, and this response was enhanced by T3. Moreover, knockdown CYP51 decreased cell viability. Meanwhile, gene knockdown also blocked T3 and FSH-induced estradiol (E2) and progesterone (P4) synthesis. These changes were accompanied by upregulation of phospho-GATA-4 content. Results of small interfering RNA analysis showed that knockdown of GATA-4 significantly diminished CYP51 gene expression as well as E2/P4 levels. Furthermore, thyroid hormone receptor β was necessary to the activation of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt), which was required for the regulation of CYP51 expression; activated GATA-4 was also involved these processes. Our data demonstrate that T3 and FSH cotreatment potentiates cellular development and steroid biosynthesis via CYP51 upregulation, which is mediated through the activation of the PI3K/Akt pathway. Meanwhile, activated GATA-4 is also involved in this regulatory system. These findings suggest that CYP51 is a mediator of T3 and FSH-induced follicular development.

Nitric Oxide-Mediated Regulation of GLUT by T3 and Follicle-Stimulating Hormone in Rat Granulosa Cells

Thyroid hormones are important for normal reproductive function. Although 3,5,3'-triiodothyronine (T3) enhances follicle-stimulating hormone (FSH)-induced preantral follicle growth and granulosa cells development in vitro, little is known about the molecular mechanisms regulating ovarian development via glucose. In this study, we investigated whether and how T3 combines with FSH to regulate glucose transporter protein (GLUT) expression and glucose uptake in granulosa cells. In this study, we present evidence that T3 and FSH cotreatment significantly increased GLUT-1/GLUT-4 expression, and translocation in cells, as well as glucose uptake. These changes were accompanied by upregulation of nitric oxide (NO) synthase (NOS)3 expression, total NOS and NOS3 activity, and NO content in granulosa cells. Furthermore, we found that activation of the mammalian target of rapamycin (mTOR) and phosphoinositide 3-kinase (PI3K)/Akt pathway is required for the regulation of GLUT expression, translocation, and glucose uptake by hormones. We also found that l-arginine upregulated GLUT-1/GLUT-4 expression and translocation, which were related to increased glucose uptake; however, these responses were significantly blocked by N(G)-nitro-l-arginine methylester. In addition, inhibiting NO production attenuated T3- and FSH-induced GLUT expression, translocation, and glucose uptake in granulosa cells. Our data demonstrate that T3 and FSH cotreatment potentiates cellular glucose uptake via GLUT upregulation and translocation, which are mediated through the activation of the mTOR/PI3K/Akt pathway. Meanwhile, NOS3/NO are also involved in this regulatory system. These findings suggest that GLUT is a mediator of T3- and FSH-induced follicular development.

Effect of azaline B on follicular development and functions in the hamster

The usefulness of azaline B, a GnRH antagonist, in suppressing gonadotropin secretion in the golden hamster was examined by examining follicular development, steroidogenesis and expression of steroidogenic enzymes. Serum levels of P and E declined significantly, while FSH or LH was undetectable in azaline B-treated hamsters. FSH significantly increased serum E levels, whereas LH upregulated serum P levels. The formation of antral follicles ceased in azaline-treated hamsters, but was reversed by FSH with or without LH supplement. FSH also activated the primordial follicle pool resulting in increased formation of primary and preantral follicles. Further, an increasing trend in the formation of preantral follicles in response to E or E + P, and the formation of antral follicles in response to E + P treatment was evident. The level of Cyp11a1 mRNA increased markedly in LH- or LH + FSH-treated hamsters, whereas FSH with or without LH upregulated Cyp17a1, Cyp19a1 and Fshr mRNA expression. E without or with P also upregulated ovarian Cyp19a1 mRNA expression. The expression of enzyme protein corroborated the mRNA data. In summary, azaline B is an efficient GnRH antagonist in the hamster, and will be useful in studying the selective effect of gonadotropins on ovarian functions without disrupting the physiological functions of other hormones in ovarian cells.

Elevated serum thyroid-stimulating hormone is associated with decreased anti-Müllerian hormone in infertile women of reproductive age

PURPOSE

Thyroid dysfunction and autoimmune thyroiditis are associated with fertility in women of reproductive age. Anti-Müllerian hormone (AMH), a known biomarker of ovarian function, may be affected by impaired thyroid function; however, the relationship between AMH and thyroid hormone has not been elucidated.

METHODS

In this case-control study, to identify the impact of thyroid hormone on ovarian reserve, we recruited 67 consecutive Japanese infertile patients and 27 normal fertile women aged 30-39 years without impact factors on thyroid and ovarian functions between 2012 and 2013. We assessed patient age, BMI and AMH, prolactin, TSH and FT4 levels of all study participations as independent variables. To evaluate the relationship between AMH and thyroid hormone, we matched patients by age and body mass index as confounding factors using 1:1 matching for statistical analysis of healthy fertile women and infertile patients and obtained 23 pairs. Then, independent variables were subjected to multiple regression analysis.

RESULTS

Multiple regression analysis showed that both thyroid-stimulating hormone (TSH) levels and patient age were negatively correlated with AMH levels in infertile patients (patient age and TSH: standardized partial regression coefficient (β), -0.534 and -0.361; p = 0.003 and 0.036, respectively), but not in normal fertile women.

CONCLUSIONS

AMH levels were inversely correlated with TSH levels in infertile women of reproductive age.