Steroid Secretion Research Articles

Ellagitannins--compounds from pomegranate as possible effector in steroidogenesis of rabbit ovaries.

This study has observed possible effect of ellagitannins - compounds from pomegranate on process of steroidogenesis in ovaries. The aim of the study was to investigate the possible effect of punicalagin on secretion of steroid hormones - progesterone, androstenedione, testosterone and 17beta-estradiol by ovarian fragments of rabbits in vitro. Ovarian fragments from sexually mature female New Zealand white rabbits (n=20) were incubated without (control group) or with punicalagin at various doses 1, 10 and 100 microg.ml(-1) for 24 h. Hormones were evaluated by ELISA (The Enzyme-Linked Immunosorbent Assay). Data showed that progesterone and 17beta-estradiol (but not androstenedione and testosterone) release by rabbit ovarian fragments was significantly affected by punicalagin addition at various doses. Punicalagin (at 100 microg.ml(-1)) significantly (P<0.05) increased progesterone secretion. On the other hand, the release of 17beta-estradiol was significantly (P<0.005) decreased by punicalagin addition (at 10 microg.ml(-1)). Our results suggest that punicalagin could have dose-dependent impact on secretion of steroid hormones progesterone and 17beta-estradiol by rabbit ovarian fragments and it may be effector in process of ovarian steroidogenesis.

Effects of 2,2′,4,4′-tetrabromodiphenyl ether (BDE47) on the enzymes of phase I (CYP2B1/2) and phase II (SULT1A and COMT) metabolism, and differences in the action of parent BDE-47 and its hydroxylated metabolites, 5-OH-BDE-47 and 6-OH-BDE47, on steroid secretion by luteal cells

In this study we determined the effects of BDE-47 on the expression and activity of phase I (CYP2B1/2) and phase II (SULT1A and COMT) enzymes, and assessed the actions of BDE-47 and its metabolites on luteal steroidogenesis. Luteal cells collected during early (ELP), middle (MLP) and late (LLP) luteal phase were exposed to BDE-47 (0.5, 25, and 50ng/ml) or metabolites (2.5, 5 and 25ng/ml). BDE-47 decreased CYP2B1/2 activity and expression but had no effect on SULT1A or COMT. BDE-47 exerted a stimulatory action on estrogen secretion in MLP and an inhibitory in LLP, but had no effect on progesterone secretion. 5-OH-BDE-47 and 6-OH-BDE-47 decreased progesterone, but had no effect on estrogen secretion. ConclusionsThe inhibitory effect of BDE-47 on CYP2B1/2 suggests the possibility of BDE-47 accumulation in the corpus luteum; by affecting steroid secretion and steroidogenesis enzymes, BDE-47 and its metabolites can be responsible for shortening luteal phase.

Steroid Profiling by LC-MS/MS in Nonsecreting and Subclinical Cortisol-Secreting Adrenocortical Adenomas.

Long-term follow-up studies revealed that patients with subclinical hypercortisolism (SH) due to adrenocortical adenomas have an increased incidence of cardiovascular diseases and mortality. No studies have yet investigated the steroid profile and its implications in patients with SH. The objective of the study was to analyze the steroid profile by liquid chromatography-tandem mass spectrometry in sera from patients with unilateral adrenocortical adenomas. This was a cross-sectional study. The study was conducted at an outpatient clinic. Patients with adrenocortical adenomas (nonsecreting, n = 66; SH, n = 28) and 188 age- and sex-matched controls drawn from the general population participated in the study. Cortisol, 21-deoxycortisol, 11-deoxycortisol, 17-hydroxyprogesterone, androstenedione, dehydroepiandrosterone, T, progesterone, 11-deoxycorticosterone, and corticosterone in the basal condition and after a 1-24 ACTH test, and clinical data were measured. Patients with SH showed lower basal and 1-24 ACTH-stimulated levels of dehydroepiandrosterone and androstenedione than those with nonsecreting adenomas and controls. T was also lower in SH females. Receiver-operating characteristic curves showed that androgens had good accuracy in predicting SH (sensitivity and specificity were 71% and 76% for dehydroepiandrosterone and 69% and 61% for androstenedione, respectively). Increased cortisol and reduced dehydroepiandrosterone levels were independently associated with increased waist circumference. Cortisol was also independently associated with increased number of cardiovascular risk factors in SH patients. After 1-24 ACTH stimulation, the SH patients also showed increased production of 21-deoxycortisol and 11-deoxycorticosterone. Liquid chromatography-tandem mass spectrometry steroid profile performed for the first time in sera from patients with adrenocortical adenomas showed impaired secretion of several steroids in SH patients. This fingerprint can help in better characterizing the functional status of these tumors.

Effects of selective serotonin reuptake inhibitors on three sex steroids in two versions of the aromatase enzyme inhibition assay and in the H295R cell assay

Selective serotonin reuptake inhibitors are known to have a range of disorders that are often linked to the endocrine system e.g. hormonal imbalances, breast enlargement, sexual dysfunction, and menstrual cycle disorders. The mechanisms behind most of these disorders are not known in details. In this study we investigated whether the endocrine effect due to SSRI exposure could be detected in well adopted in vitro steroidogenesis assays, two versions of the aromatase enzyme inhibition assay and the H295R cell assay. The five drugs citalopram, fluoxetine, fluvoxamine, paroxetine and sertraline, were shown to inhibit the aromatase enzyme in both types of aromatase assays. The IC50 values ranged from 3 to 600μM. All five SSRIs, were further investigated in the H295R cell line. All compounds altered the steroid secretion from the cells, the lowest observed effect levels were 0.9μM and 3.1μM for sertraline and fluvoxamine, respectively. In general the H295R cell assay was more sensitive to SSRI exposure than the two aromatase assays, up to 20 times more sensitive. This indicates that the H295R cell line is a better tool for screening endocrine disrupting effects. Our findings show that the endocrine effects of SSRIs may, at least in part, be due to interference with the steroidogenesis.

In the pubertal rat, the regulation of ovarian function involves the synergic participation of the sensory and sympathetic innervations that arrive at the gonad.

BackgroundThe present study investigates sectioning the superior ovarian nerve (SON) in rats with functional sensorial denervation induced by capsaicin administration at birth and the effects on the establishment of puberty, ovulation, serum progesterone, and estradiol concentrations.MethodsThe animals were allotted randomly to one of the following experimental groups. Groups of 8–10 rats were injected at birth with capsaicin or vehicle, and on day 20 or 28 of life, they were submitted to a sham operation (SO). Other groups of 8–10 rats were injected at birth with capsaicin or vehicle, and on day 20 or 28 of life, they were submitted to the uni-or bilateral SON sectioning. The animals were killed at the first estrus. Serum concentration of progesterone (ng/ml) and estradiol (pg/ml) were measured using a radioimmunoassay.ResultsAnimals treated with capsaicin and subjected at 20 days of life to the left or bilateral section of SON had a delayed age of vaginal opening. Furthermore, animals with a lack of sensory information and subjected to a SO at 28 days of life had the same delay in the age of vaginal opening. Animals with sensorial innervation intact, subjected to unilateral section of the SON at 20 or 28 days of age, showed diminished ovulation rate and number of ova shed by the denervated ovary. In animals with sensorial denervation, the uni-or bilateral sectioning of the SON did not result in changes in ovulation. Progesterone and estradiol levels were different depending on the age of the animal in which the SON section was performed.ConclusionsBased on the present results, we suggest that sympathetic innervation regulates ovulation and the secretion of steroid hormones and that the sensory fibers modulate the sympathetic innervation action on ovarian functions.

The comprehensive mechanisms underlying nonhierarchical follicular development in geese (Anser cygnoides)

The laying performance of poultry primarily depends on the growth and development of the ovarian follicles. Yet, little is known about the underlying mechanisms responsible for nonhierarchical follicular development in avian species. The aim of the present study is identify genes that are differentially expressed during nonhierarchical follicular development in geese by performing a transcriptome screen. A sequencing depth of 13.9 and 14.9 million mapped tags was obtained in pools of small white follicles (SWF) and small yellow follicles (SYF), respectively, and a total of 160 differentially expressed genes were identified. The fold-changes of eight differentially expressed genes, identified using qRT-PCR, were consistent with the Digital Gene Expression Profiling (DGE) data. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG) analyses showed that lipid metabolism, steroid secretion, extracellular ligand reactions, enzyme activities, the cell cycle, ECM–receptor interactions and the extracellular matrix are involved in follicular development. The majority of the newly identified genes could be considered to be new candidate genes with potential roles in regulating follicular development. These results provide useful information for future in-depth studies associated with nonhierarchical follicular development in goose reproduction.

Expression and localization of the diacylglycerol kinase family and of phosphoinositide signaling molecules in adrenal gland.

Adrenal glands play a central role in the secretion of steroid hormones and catecholamines. Previous studies have revealed that molecules engaged in phosphoinositide (PI) turnover are expressed in the adrenal gland, suggesting the importance of PI signaling in adrenal signal transduction. Diacylglycerol kinase (DGK) catalyzes the phosphorylation of diacylglycerol (DG), a major second messenger in the PI signaling cascade. The DGK family is expressed in distinct patterns in endocrine organs at the mRNA and protein levels. Nevertheless, little is known about the characteristics and morphological aspects of DGKs in the adrenal gland. We have performed immunohistochemical analyses to investigate the expression and localization of DGK isozymes, together with PI signaling molecules, in the adrenal gland at the protein level. Our results show that the DGK family and a set of PI signaling molecules are expressed intensely in zona glomerulosa cells and medullary chromaffin cells in the adrenal gland. In adrenal cells, DGKγ localizes to the Golgi complex, DGKε to the plasma membrane, and DGKζ to the nucleus. These findings show the distinct expression and subcellular localization of DGK isozymes and PI signaling molecules in the adrenal gland, suggesting that each DGK isozyme has a role in signal transduction in adrenal cells, especially in the zona glomerulosa and medulla.

Tentative Differentiation of Interstitial Cells during Preparatory Phase of &lt;em&gt;Heteropneustes fossilis&lt;/em&gt; (Bl.) Under Long Photoperiod

Present paper deals with the impact of a long photoperiod (18 h) per day for 45 days on steroid secreting interstitial cells during preparatory phase of a freshwater cat fish, Heteropnuestes fossilis (Bl.). Depending upon the histocytological structure and secretory status, interstitial cells have been grouped into four categories revealing their corresponding functional status.

Analysis of gonadal steroid secretion in the serum of women during ovarian stimulation

Analysis of gonadal steroid secretion in the serum of women during ovarian stimulation

The Effects of Phytoestrogen Genistein on Steroidogenesis and Estrogen Receptor Expression in Porcine Granulosa Cells of Large Follicles.

Genistein is a biologically active isoflavone with estrogenic or antiestrogenic activity which can be found in a variety of soy products. Since in pigs' diet soy is the main source of protein, genistein may affect the reproductive/endocrine systems in these animals. Genistein has been shown to alter porcine ovarian and adrenal steroidogenesis but the mechanism of this action is still not clear. It is known that genistein binds to both estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ), although it has a higher affinity to ERβ. Moreover, this phytoestrogen was demonstrated to posses the activity of protein tyrosine kinase (PTK) inhibitor. The aim of the study was to examine the in vitro effects of genistein on: (1) progesterone (P4) and estradiol (E2) secretion by porcine luteinized granulosa cells harvested from large follicles, and (2) the mRNA and protein expression of ERa and ERβ in these cells. In addition, to verify the role of PTK-dependent mechanisms possibly involved in genistein biological action, we tested the effects of lavendustin C, the nonsteroidal PTK inhibitor, on granulosa cell steroidogenesis. Genistein significantly inhibited P4 and did not affect E2 secretion by porcine luteinized granulosa cells isolated from large follicles. Lavendustin C did not affect basal steroids secretion by examined cells. Genistein did not alter ERa but increased ERβ mRNA levels in the cultured porcine granulosa cells. In contrast to medium follicles, the expression of ERβ protein was unaffected by genistein in granulosa cells of large follicles. To conclude, the soy phytoestrogen genistein acts directly on the porcine ovary to decrease progesterone production and to increase the expression of ERβ mRNA. Moreover, genistein-induced changes in follicular steroidogenesis and granulosal sensitivity to estrogens in pigs may depend on maturity of the follicles.

Regulatory Role of Gonadotropins and Local Factors Produced by Ovarian Follicles on In Vitro Resistin Expression and Action on Porcine Follicular Steroidogenesis.

Resistin, a hormone secreted by adipocytes, is thought to be important in reproduction. Our previous study demonstrated resistin expression in porcine ovarian follicles and its direct effect on steroidogenesis. The aim of the current study was to evaluate the effect of gonadotropins and the local ovarian factors, such as insulin-like growth factor type 1 (IGF1) and steroids (progesterone, testosterone, and 17 beta-estradiol), on the expression and secretion of resistin, as well as its steroidogenic action. Porcine ovarian follicles were exposed to follicle-stimulating hormone (FSH) and luteinizing hormone (LH) at 50-150 ng/ml, IGF1 (10-100 ng/ml), and steroids at 10(-8) to 10(-6) M for 24 h. Then, mRNA, protein expression, and medium concentration of resistin were determined using real-time PCR, Western blot analysis, and ELISA, respectively. In the subsequent experiments, ovarian follicles were exposed to resistin and/or FSH, LH, IGF1, and steroids, and ovarian steroidogenesis was analyzed. Additionally, we examined the direct effect of resistin on the protein expression of receptors for gonadotropins and investigated local factors. The results showed that gonadotropins and steroids have stimulatory effects but that IGF1 has an inhibitory effect on resistin expression and secretion. Resistin decreased gonadotropins and local hormone-induced steroid secretion and inhibited 3beta-hydroxysteroid dehydrogenase, 17beta-hydroxysteroid dehydrogenase, and cytochrome P450 aromatase protein expression. Additionally, we demonstrated that resistin increased the expression of receptors for progesterone and testosterone. These findings all show that the expression and function of resistin are regulated by gonadotropins and local factors produced by ovarian follicles.

Steroidogenic enzyme profile in an androgen-secreting adrenocortical oncocytoma associated with hirsustism.

Hirsutism induced by hyperandrogenism can be associated with polycystic ovary syndrome, 21-hydroxylase (OH) deficiency or androgen-secreting tumors, including ovarian and adrenal tumors. Adrenal androgen-secreting tumors are frequently malignant. Adrenal oncocytomas represent rare causes of hyperandrogenism. The aim of the study was to investigate steroidogenic enzyme expression and steroid secretion in an androgen-secreting adrenal oncocytoma in a young woman presenting with hirsutism. Hyperandrogenism was diagnosed on the basis of elevated plasma Δ4-androstenedione and testosterone levels. Pelvic ultrasound was normal, CT scanning revealed a right adrenal mass. Androgens were assessed in adrenal and ovarian vein samples and proved a right adrenal origin. Adrenalectomy normalized androgen levels and the adrenal tumor was diagnosed as an oncocytoma. Real time-PCR, immunohistochemistry and cell culture studies were performed on tumor explants to investigate the steroid secretion profile. Among enzymes required for cortisol synthesis, 17α-OH and 3β-hydroxysteroid dehydrogenase 2 (3β-HSD2) were highly expressed whereas 21-OH and 11β-OH were weakly produced at the mRNA and/or protein levels. Enzymes involved in testosterone production, 17β-HSD5 and 17β-HSD3, were also detected. ACTH receptor was present in the tissue. Cortisol, Δ4-androstenedione and testosterone secretions by cultured cells were increased by ACTH. These results provide the first demonstration, to our knowledge, of abnormal expression profile of steroidogenic enzymes in an adrenocortical oncocytoma. Our results also indicate that Δ4-androstenedione hypersecretion resulted from high 17α-OH and 3β-HSD2 expression in combination with low expression of 21-OH and 11β-OH. Testosterone production was ascribed to occurrence of 17β-HSD5 and 17β-HSD3. Finally, our results indicate that androgen secretion was stimulated by ACTH.

Etiology, diagnosis and management of adrenal insufficiency in children

Adrenal insufficiency(AI) is a disorder that can result from primary adrenal failure(primary type) or secondary adrenal disease due to impairment of the hypothalamic–pituitary axis(central type). It is characterized by glucocorticoid deficiency, with or without inappropriate mineralocorticoid or androgen production.The diagnosis and management of children with AI remain challenging as clinical characteristics of AI in children maybe non-specific and acute adrenal crisis is life-threatening, needing life-long glucocorticoid replacement treatment and education of the patient and the family.New formulations of hydrocortisone which should be able to simulate the circadian rhythm of steroid secretion are supposed to improve outcome in patients with adrenal insufficiency in the near future. Key words: Adrenal insufficiency; Adrenal crisis; Glucocorticoid; Mineralocorticoid

Assessment of a potential preventive ability of amygdalin in mycotoxin-induced ovarian toxicity

The possible effects of a natural substance amygdalin and its combination with the mycotoxin deoxynivalenol (DON) on the steroid hormone secretion (progesterone and 17-β-estradiol) by porcine ovarian granulosa cells (GCs) were examined in this in vitro study. Ovarian GCs were incubated without (control group) and with amygdalin (1, 10, 100, 1,000 and 10,000 μg mL1), or its combination with DON (1 μg mL1) for 24 h. The release of steroid hormones was determined by ELISA. The progesterone secretion by porcine ovarian GCs was not affected by amygdalin in comparison to the control. However, the highest amygdalin dose (10,000 μg mL1) caused a significant stimulation of the 17-β-estradiol release. A combination of amygdalin with DON significantly (P < 0.05) increased the progesterone release at all concentrations. Similarly, a stimulatory effect of amygdalin co-administered with DON was detected with respect to the 17-β-estradiol secretion at the highest dose (10,000 μg mL1) of amygdalin and 1 μg mL1 of DON. Noticeable differences between the effects of amygdalin alone and its combination with DON on the progesterone release were detected. In contrast, no differences between the stimulatory effects of amygdalin and its combination with DON on the 17-β-estradiol synthesis by porcine GCs were observed. Findings from this in vitro study did not confirm the expected protective effect of amygdalin on mycotoxin induced reprotoxicity. Our results indicate that the stimulatory effect of amygdalin combined with DON on the progesterone release was clearly caused by the DON addition, not by the presence amygdalin per se. On the other hand, the stimulation of 17-β-estradiol production was solely caused by the presence of amygdalin addition. These findings suggest a possible involvement of both natural substances into the processes of steroidogenesis and appear to be endocrine modulators of porcine ovaries.

Food, stress, and circulating testosterone: Cue integration by the testes, not the brain, in male zebra finches (Taeniopygia guttata)

Food abundance is closely associated with reproductive readiness in vertebrates. Food scarcity can activate the hypothalamo–pituitary–adrenal axis, decrease sex steroid secretion, and dampen reproductive behavior. However, the mechanisms underlying these transient effects are unclear. Gonadotropin inhibitory hormone (GnIH), a neuropeptide present in the brain and gonads, is also influenced by glucocorticoids and fasting in some species. We investigated whether fasting stress activated the GnIH system in zebra finches (Taeniopygia guttata), with the potential for downstream effects on reproductive physiology and behavior. We fasted or fed males ad libitum for 10h. Fasting increased corticosterone and decreased testosterone in circulation. To assess whether the decrease in testosterone was mediated by changes in the hypothalamus and/or the gonads, we (1) quantified GnRH- and GnIH-positive neurons in the hypothalamus, (2) assessed hypothalamic gene expression for GnRH and GnIH, and (3) examined gene expression for proteins involved in testosterone synthesis in fasted and control birds. No measure of hypothalamic neuropeptides was related to treatment or circulating steroids. However, birds with higher corticosterone had higher testicular GnIH expression and lower testosterone. StAR and LHR expression were lower in the testes of fasted birds than controls. Thus, the decrease in testosterone was not likely mediated by hypothalamic GnIH, but rather by direct actions of fasting and/or corticosterone on the testes, indicating that the testes can integrate and respond to cues of stress directly. Such local inhibition of testosterone synthesis may allow for rapid and reversible changes in physiology and behavior when conditions are inappropriate for breeding.

Ghrelin negatively affects the function of ovarian follicles in mature pigs by direct action on basal and gonadotropin-stimulated steroidogenesis.

We previously showed that expression of ghrelin messenger RNA is significantly increased in the ovaries of cycling pigs but not in prepubertal animals and that ghrelin stimulates estradiol (E2) secretion by ovarian follicles in prepubertal animals. The present study investigated in vitro the role of ghrelin in regulating the ovarian steroidogenesis during estrus cycle in mature pigs. Small (SFs), medium (MFs), and large (LFs) ovarian follicles were collected on days 4 to 6, 10 to 12, and 16 to 18 of the estrous cycle from cycling pigs and exposed to 20, 100, and 500 pg/mL ghrelin for 24 hours. In additional experiments, MFs were exposed to ghrelin plus 100 ng/mL follicle-stimulating hormone (FSH) or luteinizing hormone (LH). Levels of progesterone (P4), testosterone (T), and E2 in culture medium were determined by enzyme-linked immunosorbent assay, and the expression of the steroid pathway enzymes 3β hydroxysteroid dehydrogenase (HSD), 17β-HSD, and cytochrome P450 aromatase (CYP19) was evaluated by Western blotting. Ghrelin had no effect on steroid secretion when present at 20 pg/mL, its concentration in follicular fluid, whereas at 100 pg/mL and 500 pg/mL, its concentration in serum, ghrelin significantly decreased secretion of P4, T, and E2. Moreover, all concentrations of ghrelin decreased steroid secretion in FSH- and LH-stimulated follicles. Western blot analysis showed that ghrelin inhibited expression of 3β-HSD, 17β-HSD, and CYP19 proteins. These results suggest that ghrelin, by direct inhibition of 3β-HSD, 17β-HSD, and CYP19 protein expression, inhibits LH- and FSH-stimulated steroid secretion by ovarian follicles, thus negatively affecting ovarian steroidogenesis in mature pigs.

Very low-dose (femtomolar) 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) disrupts steroidogenic enzyme mRNAs and steroid secretion by human luteinizing granulosa cells.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is the most toxic congener of the polyhalogenated aromatic hydrocarbons (PAH), which causes anatomical abnormalities and developmental defects, impairs ovulation and reduces fertility. TCDD's endocrine-disrupting effects are, in part, caused by a direct action at the ovary. Herein we investigated the in-vitro effects of environmentally relevant doses of TCDD on estradiol-17β (E2) production by human luteinizing granulosa cells (hLGC) obtained from women stimulated for in-vitro fertilization (IVF). TCDD at all concentrations tested (3.1fM, 3.1pM and 3.1nM) significantly decreased E2 secretion when assayed for by radioimmunoassay (RIA). Herein we confirm that TCDD alters E2 secretion by hLGC in a time-, not dose-dependent fashion and are the first to show decreases in E2 secretion with fM concentrations of TCDD. Using real-time quantitative PCR (RT-qPCR), the decreased E2 secretion correlates with a decrease in the mRNA expression levels two enzymes in the estrogen biosynthesis pathway: CYP11A1 and CYP19A1.

Cortisol Administration Induces Sex Change from Ovary to Testis in the Protogynous Wrasse, Halichoeres trimaculatus

Steroid hormones have been shown to play important roles in triggering sex change. However, the upstream mechanism that regulates the secretion of sex steroid hormones controlling sex change is not yet known. Cortisol, the primary glucocorticoid in teleost fish, is known to exhibit anti-stress action and is involved in many physiological functions, including regulation of steroidogenesis. Therefore, cortisol could be one of the candidate factors involved in the onset of sex change. In this study, we investigated the role of cortisol in sex change in the three-spot wrasse, Halichoeres trimaculatus, by prolonged administration of cortisol. Our results showed that gonads of all individuals treated with cortisol (1,000 µg/g diet) for 6 weeks contained spermatogenic germ cells. One of them exhibited matured testes with an ovarian cavity, indicating sex change. Additionally, the plasma estradiol-17β level in the cortisol treatment group was significantly lower than in the control group suggesting that cortisol plays a direct and/or indirect role in the regulation of estrogen production. These data imply that cortisol might be involved in the regulation of steroidogenesis by causing a decrease in the estrogen level, leading to the onset of sex change.

Adipose tissue dysfunction, adipokines, and low-grade chronic inflammation in polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS), a complex condition that affects women of reproductive age, is characterized by ovulatory dysfunction and androgen excess. Women with PCOS present higher prevalence of obesity, central adiposity, and dyslipidemia, and face increased risk of type 2 diabetes. PCOS is closely linked to functional derangements in adipose tissue. Adipocytes seem to be prone to hypertrophy when exposed to androgen excess, as experienced by women with PCOS, and both adipose tissue hypertrophy and hyperandrogenism are related to insulin resistance. Hypertrophic adipocytes are more susceptible to inflammation, apoptosis, fibrosis, and release of free fatty acids. Disturbed secretion of adipokines may also impact the pathophysiology of PCOS through their influence on metabolism and on sex steroid secretion. Chronic low-grade inflammation in PCOS is also related to hyperandrogenism and to the hypertrophy of adipocytes, causing compression phenomena in the stromal vessels, leading to adipose tissue hypoperfusion and altered secretion of cytokines. Lifestyle changes are the first-line intervention for reducing metabolic risks in PCOS and the addition of an insulin-sensitizing drug might be required. Nevertheless, there is not sufficient evidence in favor of any specific pharmacologic therapies to directly oppose inflammation. Further studies are warranted to identify an adipokine that could serve as an indirect marker of adipocyte production in PCOS, representing a reliable sign of metabolic alteration in this syndrome.

Effect of BMP-6 on development and maturation of mouse preantral follicles in vitro

The aim of this study was to investigate the effect and mechanism of bone morphogenetic protein-6 (BMP-6) on the growth and maturation of mouse follicles in vitro. Preantral follicles isolated from mice were incubated with recombinant human BMP-6 (rhBMP-6) before analysis. BMP-6 expression was detected by immunofluorescence and western blot. Maturation of oocytes was observed microscopically. Estradiol (E2) and progesterone (P4) levels were measured by enzyme-linked immunosorbent assay. Expression of steroidogenesis-related genes was detected by reverse transcription quantitative polymerase chain reaction. There was a marked increase in the preantral follicles maturation in cells incubated with 50 ng/mL of rhBMP-6 for eight days, compared with the control. The levels of E2, P4 and steroidogenesis-related genes were also significantly increased in granulosa cells and theca cells cultured for 6, 10 and 11 days, respectively. Conversely, the preantral follicle maturing rate was remarkably decreased in cells incubated with 50 ng/mL of rhBMP-6 for day 11, accompanied with reduction in E2, P4 levels and steroidogenesis-related genes levels. Meanwhile, compared with the control, the maturing rate was not significantly different in cells incubated with 100 ng/mL of rhBMP-6 for day 8 or day 11. However, the E2 levels and its relevant regulation gene expression all increased significantly, while the P4 content and its relevant regulation gene expression decreased. The results indicate that BMP-6 can promote the maturation of preantral follicles in vitro in a concentration and time-dependent manner and may play a role in the regulation of steroid hormone synthesis and/or secretion.