neuropeptide-y and Polycystic-Ovary-Syndrome

Insulin, ghrelin, neuropeptide Y (NPY) and leptin interact in the regulation of energy homeostasis. Most of these signals are altered in polycystic ovary syndrome (PCOS), which is characterized by a high prevalence of obesity. The present study was conducted to evaluate ghrelin-NPY and ghrelin-leptin interplays in relation to insulin secretion in obese PCOS subjects.. Pilot prospective study.. Seven obese PCOS women and seven age-weight matched controls.. Hormonal measurements, oral glucose tolerance test (OGTT) and a ghrelin test (1 microg/kg i.v. bolus). PCOS patients repeated the clinical work-up after 4 months of metformin treatment (1500 mg/day orally).. At baseline, PCOS women showed a significantly higher insulinaemic response to the OGTT compared to controls (P < 0.05). In basal conditions, PCOS women exhibited lower NPY levels than controls (P < 0.01). Ghrelin injection markedly increased NPY in controls (P < 0.01), whereas PCOS women showed a deeply blunted NPY response to the stimulus (area under the curve--AUC-NPY: P < 0.01 vs. controls.). Metformin treatment induced a significant decrease in insulin levels (P < 0.01) and the concomitant recovery of NPY secretory capacity in response to ghrelin (AUC-NPY: P < 0.05 vs. baseline) in PCOS women. Leptin levels, which were similar in the two groups, were not modified by ghrelin injection; metformin did not affect this pattern.. Hyperinsulinaemia seems to play a pivotal role in the alteration of NPY response to ghrelin in obese PCOS women. This derangement could be implicated in the physiopatology of obesity in these patients.

Topics: Adult; Female; Ghrelin; Glucose Tolerance Test; Humans; Hyperinsulinism; Hypoglycemic Agents; Insulin; Leptin; Metformin; Neuropeptide Y; Obesity; Pilot Projects; Polycystic Ovary Syndrome; Signal Transduction; Young Adult

To evaluate the effect of rosiglitazone on insulin resistance and hyperandrogenism in polycystic ovary syndrome (PCOS).. Rosiglitazone was given 4 mg daily to 30 patients with PCOS for 12 weeks. Before and after treatment, body mass index (BMI), plasma glucose, insulin, levels insulin resistance index (HOMA IR), blood lipid spectrum, leptin, neuropeptide Y, and sex hormone concentrations and ovulation rate were determined and compared.. After 12 weeks of treatment, basal insulin level decreased from (18 +/- 8) to (12 +/- 7) mIU/L (P < 0.01), HOMA IR decreased from 4.3 +/- 1.2 to 2.6 +/- 0.7 (P < 0.01). Luteinizing hormone, free testosterone and androstenedione levels decreased [(15.4 +/- 4.4) versus (7.9 +/- 2.1) U/L, (12.5 +/- 1.9) versus (8.9 +/- 1.4) pmol/L, (9.8 +/- 1.7) versus (7.4 +/- 1.2) nmol/L respectively, P < 0.01]; Dehydroepiandrosterone sulfate level also decreased [(8.7 +/- 3.5) versus (6.9 +/- 2.1) micromol/L, P < 0.05]; Sex hormone binding globulin level increased [(39 +/- 3) versus (58 +/- 5) nmol/L, P < 0.01]. Plasma leptin level was decreased [(18 +/- 4) versus (13 +/- 3) microg/L, P < 0.01]. Ovulation rate increased to 50%.. Rosiglitazone might decrease plasma leptin level and improve insulin sensitivity, which led to alleviation of hyperandrogenism and resumption of ovulation and menses in patients with PCOS.

Topics: Administration, Oral; Adult; Androstenedione; Blood Glucose; Body Weight; Female; Follicle Stimulating Hormone; Humans; Hyperandrogenism; Hypoglycemic Agents; Insulin; Insulin Resistance; Leptin; Lipids; Luteinizing Hormone; Menstruation; Neuropeptide Y; Ovulation; Polycystic Ovary Syndrome; Rosiglitazone; Testosterone; Thiazoles; Thiazolidinediones; Treatment Outcome

Most women with anovulatory infertility show polycystic ovarian syndrome (PCOS), and androgen excess is known as a key factor involved in pathogenicity of PCOS. However, the mechanism of follicular developmental arrest in PCOS is not completely understood. The reproductive function of Neuropeptide Y (NPY) in the ovary during folliculogenesis was previously reported; NPY function in apoptosis and proliferation of granulosa cells (GCs) is follicular-stage dependent. The objective of this study was to investigate the role of NPY in ovarian follicular development and the pathogenesis of PCOS.. To simulate the PCOS phenotype using a rat model, 21-day old Sprague Dawley rats were implanted with dihydrotestosterone (DHT) capsule (83 µg/day) and euthanized after 28 days. mRNA and protein content of NPY and its receptors were assessed in GCs from DHT treated rats using RT-qPCR and Western blot, respectively. Proliferation and apoptosis of GCs was assessed using Ki67- and TUNEL assays. Finally, NPY levels were measured in human follicular fluid (FF) from matched PCOS and non-PCOS patients using ELISA.. GCs from DHT treated rats (PCOS-GCs) contained significantly less NPY protein and Npy mRNA by 0.16- and 0.56-fold, respectively, and more NPY receptor type 2 and 5 protein by 2.21- and 3.17-fold, respectively, when compared to sham control. Addition of recombinant NPY to PCOS-GCs culture did not alter Ki67-positive but significantly decreased TUNEL-positive cells by 0.65-fold, but not to baseline levels. There was no significant difference in NPY levels in FF between PCOS and non-PCOS subjects.. These results indicate that DHT modulates expression of NPY and its receptors, NPY decreases DHT-induced GCs apoptosis. That alterations in NPY's function might be involved in follicular developmental failure of PCOS.

Topics: Animals; Apoptosis; Dihydrotestosterone; Female; Granulosa Cells; Humans; Ki-67 Antigen; Neuropeptide Y; Polycystic Ovary Syndrome; Rats; Rats, Sprague-Dawley; RNA, Messenger

Polycystic ovary syndrome (PCOS) is a common reproductive and metabolic disorder characterized by high androgen levels. The aim of this study was to evaluate the effects of hyperandrogenism on the hypothalamus and subsequently on the food intake and obesity in females.. A dihydroxy testosterone (DHT)-induced rat model was established to recapitulate the hyperandrogenism features of PCOS patients. Body weight and food intake of the rats were recorded. The food intake of DHT-induced rats was restricted by pair feeding to exclude possible effects of weight gain on the hypothalamus. The expression levels of relevant proteins and mRNAs in the hypothalamus and primary hypothalamic neurons exposed to DHT were analyzed by Western blotting and RT-PCR, respectively. The leptin levels in the serum and cerebrospinal fluid (CSF) were measured, and leptin was injected via the intracerebroventricular (ICV) route to test the leptin sensitivity of the hypothalamus.. The excessive prepuberty androgen levels in the DHT-induced rats markedly elevated food intake prior to weight gain. Consistent with this, the expression of neuropeptide Y and agouti-related peptide mRNAs was upregulated, which occurred prior to obesity and even with restricted food intake. In addition, the hypothalamic sensitivity to insulin and leptin was also impaired in the DHT-induced rats before obesity and with restricted food intake. DHT significantly reduced the leptin levels in the CSF, and ICV injection of leptin inhibited the DHT-induced increase in food intake.. Androgen excess increased food intake in rats and promoted obesity by downregulating insulin and leptin signaling in the hypothalamus, most likely by suppressing leptin levels in the CSF.

Topics: Androgens; Animals; Body Weight; Eating; Female; Humans; Hyperandrogenism; Hypothalamus; Insulin; Leptin; Neuropeptide Y; Obesity; Polycystic Ovary Syndrome; Rats; RNA, Messenger; Signal Transduction; Testosterone; Weight Gain

Polycystic ovary syndrome (PCOS) is characterized by ovarian dysfunction, clinical and/or biochemical hyperandrogenism, and polycystic ovaries. Its pathogenesis is still unclear. This study aimed to investigate the relationship between kisspeptin, leptin, neuropeptide Y (NPY), and neurokinin B (NKB) levels for evaluating the pathogenesis of PCOS.. Levels of these parameters were analyzed in 20 patients with PCOS, and 16 healthy adolescents.. Serum NPY levels were significantly higher in the obese and non-obese PCOS group (p<0.01). There was a negative correlation between the kisspeptin and the NKB levels (p<0.01) in the PCOS group but not in the control group. This negative correlation was also found in both PCOS groups (p<0.01). In the obese PCOS group, serum kisspeptin levels were significantly lower than the control and non-obese PCOS groups (p<0.05) although serum leptin and NPY levels were significantly higher in the obese PCOS group (p<0.01).. The high NPY levels in both obese and non-obese patients with PCOS indicate that NPY plays a role in the pathogenesis independently from obesity. Significantly high leptin and low kisspeptin levels in the obese PCOS group suggested that they may be associated with obesity rather than PCOS.

Topics: Adolescent; Body Mass Index; Female; Humans; Kisspeptins; Leptin; Neurokinin B; Neuropeptide Y; Polycystic Ovary Syndrome

Polycystic ovary syndrome often starts in puberty, and its pathogenesis is not clear. This study aimed to explore the pathogenesis of pubertal polycystic ovary syndrome (PCOS) and assess the therapeutic effect of electroacupuncture on pubertal PCOS.. Dihydrotestosterone (DHT) was used to induce rat models of pubertal PCOS. pubertal rats with PCOS were randomly divided into a model group (M), an electroacupuncture group (EA), and a sham acupuncture group (SA). Age-matched normal rats were regarded as normal controls (N). Rats were treated with EA or SA five times a week for 25 minutes during their 6th-7th week. At the end of the experiment, we observed any changes in ovarian morphology; detected levels of metabolic indices in serum, the hypothalamus and pancreas.. EA significantly improved estrous cycle disorders and the ovarian polycystic morphology in pubertal rats with PCOS, but SA only improved disorders of the estrous cycle. The serum levels of insulin, neuropeptide Y(NPY) and fasting blood glucose(FBG) increased significantly (both p < 0.01), while the serum levels of ghrelin(GHRL) decreased in the model group (p < 0.01). After treatment with EA, the levels of NPY (p < 0.01) and FBG (p < 0.05) went into decrease, whereas the levels of GHRL (p < 0.05) and insulin (p < 0.01) increased. There was few differences in the hypothalamic expression of galanin (GAL), galanin-like peptide (GALP) and ghrelin receptor(GHSR) between the four groups. The upregulation of NPY mRNA and neuropeptide Y2 receptor(NPY2R) mRNA and the downregulation of GHRL protein and mRNA in the hypothalamus, and the increased expression of NPY and NPY2R as well as the decreased expression of GHRL in the arcuate nucleus (ARC) can be rescued by EA. But, surprisingly, SA seem to make no difference to the levels of FBG and insulin, and the protein expression of ghrelin in the hypothalamus and ARC. Co-expression of kisspeptin and GHSR, and co-expression of gonadotrophin releasing hormone(GnRH) and NPY2R were observed in ARC. No differences were found between groups in protein of GAL, GALP and GHRL expression in the pancreas. Neither EA nor SA can attenuate the upregulated kisspeptin protein expression in the pancreas of PCOS model rats.. EA and SA improved the symptoms of pubertal PCOS rats, and the mechanism might be associated with regulating hypothalamic NPY and ghrelin levels.

Topics: Animals; Electroacupuncture; Female; Ghrelin; Humans; Hypothalamus; Insulins; Kisspeptins; Neuropeptide Y; Polycystic Ovary Syndrome; Rats; RNA, Messenger; Sexual Maturation

The central regulation of fertility is carefully coordinated with energy homeostasis, and infertility is frequently the outcome of energy imbalance. Neurons in the hypothalamus expressing neuropeptide Y and agouti-related peptide (NPY/AgRP neurons) are strongly implicated in linking metabolic cues with fertility regulation.. We aimed here to determine the impact of selectively activating NPY/AgRP neurons, critical regulators of metabolism, on the activity of luteinizing hormone (LH) pulse generation.. We employed a suite of in vivo optogenetic and chemogenetic approaches with serial measurements of LH to determine the impact of selectively activating NPY/AgRP neurons on dynamic LH secretion. In addition, electrophysiological studies in ex vivo brain slices were employed to ascertain the functional impact of activating NPY/AgRP neurons on gonadotropin-releasing hormone (GnRH) neurons.. Selective activation of NPY/AgRP neurons significantly decreased post-castration LH secretion. This was observed in males and females, as well as in prenatally androgenized females that recapitulate the persistently elevated LH pulse frequency characteristic of polycystic ovary syndrome (PCOS). Reduced LH pulse frequency was also observed when optogenetic stimulation was restricted to NPY/AgRP fiber projections surrounding GnRH neuron cell bodies in the rostral preoptic area. However, electrophysiological studies in ex vivo brain slices indicated these effects were likely to be indirect.. These data demonstrate the ability of NPY/AgRP neuronal signaling to modulate and, specifically, reduce GnRH/LH pulse generation. The findings suggest a mechanism by which increased activity of this hunger circuit, in response to negative energy balance, mediates impaired fertility in otherwise reproductively fit states, and highlight a potential mechanism to slow LH pulsatility in female infertility disorders, such as PCOS, that are associated with hyperactive LH secretion.

Topics: Agouti-Related Protein; Animals; Disease Models, Animal; Female; Gonadotropin-Releasing Hormone; Hunger; Luteinizing Hormone; Male; Mice; Mice, Transgenic; Nerve Net; Neurons; Neuropeptide Y; Polycystic Ovary Syndrome; Pregnancy; Prenatal Exposure Delayed Effects; Secretory Pathway

The pathogenesis of polycystic ovary syndrome (PCOS) and obesity is not clarified yet. But some parameters such as neuropeptide Y (NPY), angiopoietin-like protein (Angptl-4), omentin-1 are thought to be involved in this pathogenesis. In this study, we aimed to show possible effects of NPY, Angptl-4, omentin-1 throughout clinical parameters and hormones. Patients were divided into three groups. Group I; healthy volunteers, Group II; non-obese women with PCOS and group III; obese women with PCOS. Serum NPY, Angptl-4, free testosterone, total testosterone, luteinize hormone, sex hormone binding globulin, estradiol, dehydroepiandrosterone sulfate, androstenedione, triglycerides and low density lipoprotein cholesterol levels and HOMA-IR, Ferriman-Galwey scores were significantly higher in group II when compared with group I and similarly in group III when compared with group II (p < 0.005). While comparing all PCOS patients (obese + non-obese) with healthy volunteers, omentin-1 and high density lipoprotein cholesterol levels were significantly low in PCOS group (p < 0.005). As a result of this study, both in the obese and non-obese PCOS patients, there was a significant increase in levels of NPY and Angptl-4 and a significant decline in omentin-1 when compared to healthy subjects. In conclusion, insulin resistance in PCOS patients may be related to the differences of NPY, Angptl-4 and omentin-1 levels and the effects of these differences on metabolic pathways.

Topics: Adult; Androstenedione; Angiopoietin-Like Protein 4; Angiopoietins; Case-Control Studies; Cholesterol, HDL; Cholesterol, LDL; Cytokines; Dehydroepiandrosterone Sulfate; Estradiol; Female; GPI-Linked Proteins; Humans; Insulin Resistance; Lectins; Luteinizing Hormone; Neuropeptide Y; Obesity; Polycystic Ovary Syndrome; Sex Hormone-Binding Globulin; Testosterone; Triglycerides

Five to ten percent of women of reproductive age suffer from polycystic ovary syndrome (PCOS). Leptin, NPY, galanin, cholecystokinin (CCK) are involved in the regulation of eating behavior. PPARγ are receptors that are probably involved in hyperandrogenism. This study was designed to assess associations between the Pro12Ala PPARγ2 gene polymorphism and satiety factors in PCOS. Fifty-four PCOS women and 51 healthy women were studied. Leptin, NPY, galanin, CCK levels, and genetic studies to detect Pro12Ala PPARγ2 gene polymorphism were assessed. The leptin levels in the PCOS women carrying Pro12Ala genotype were higher than in those with Pro12Pro and Ala12Ala. The PCOS women had higher leptin and NPY levels and lower galanin levels. Obese PCOS patients had lower CCK levels.. In the PCOS women, a single Ala allele may have a protective role as far as hyperleptinemia is concerned. The PCOS women may reveal a disrupted central leptin/NPY feedback loop with some shifts in food intake.

Topics: Adult; Body Mass Index; Cholecystokinin; Female; Galanin; Genotype; Humans; Hyperandrogenism; Insulin Resistance; Leptin; Neuropeptide Y; Obesity; Polycystic Ovary Syndrome; Polymorphism, Genetic; PPAR gamma; Satiation

Altered activity of the sympathetic nervous system, which innervates adipose and ovarian tissue, may play a role in polycystic ovary syndrome (PCOS). We hypothesize that electro-acupuncture (EA) and physical exercise reduce sympathetic activity by stimulating ergoreceptors and somatic afferent pathways in muscles. Here we investigated the effects of low-frequency EA and physical exercise on mRNA expression of sympathetic markers in adipose tissue and on ovarian morphology in female rats that received dihydrotestosterone (DHT) continuously, starting before puberty, to induce PCOS. At age 11 wk, rats with DHT-induced PCOS were randomly divided into three groups: PCOS, PCOS plus EA, and PCOS plus exercise. The latter two groups received 2-Hz EA (evoking muscle twitches) three times/week or had free access to a running wheel for 4-5 wk. In mesenteric adipose tissue, expression of beta(3)-adrenergic receptor (ADRB3), nerve growth factor (NGF), and neuropeptide Y (NPY) mRNA was higher in untreated PCOS rats than in controls. Low-frequency EA and exercise downregulated mRNA expression of NGF and NPY, and EA also downregulated expression of ADRB3, compared with untreated rats with DHT-induced PCOS. EA and exercise improved ovarian morphology, as reflected in a higher proportion of healthy antral follicles and a thinner theca interna cell layer than in untreated PCOS rats. These findings support the theory that increased sympathetic activity contributes to the development and maintenance of PCOS and that the effects of EA and exercise may be mediated by modulation of sympathetic outflow to the adipose tissue and ovaries.

Topics: Acupuncture Therapy; Adipose Tissue; Animals; Dihydrotestosterone; Disease Models, Animal; Exercise Therapy; Female; Gene Expression Regulation; Nerve Growth Factor; Neuropeptide Y; Ovary; Polycystic Ovary Syndrome; Rats; Rats, Wistar; Receptors, Adrenergic, beta-3; Receptors, Androgen; RNA, Messenger; Sympathetic Nervous System

It has been reported that polycystic ovary syndrome (PCOS) is very frequently associated with obesity, insulin resistance and hyperinsulinemia. However, metabolic disorders may lead to suppression of reproductive hormone secretion during undernutrition and in obesity. Some neuropeptides, such as neuropeptide Y (NPY) and galanin, modulate the control of appetite and play an important role in the mechanism of luteinizing hormone-releasing hormone (LHRH) secretion. NPY and galanin regulate appetite via both central and peripheral mechanisms. The interaction between central and peripheral signals for the control of food intake is due to leptin. Leptin can modulate the activity of NPY and other peptides in the hypothalamus that are known to affect eating behavior. In order to evaluate the relationship between NPY, galanin and leptin, 28 women with PCOS, 32 obese women (non-PCOS) and 19 lean healthy women (control group) were investigated. Obese women with PCOS were divided into two groups: PCOS (A) overweight (body mass index, BMI 26-30 kg/m2), and PCOS (B) obese (BMI 31-40 kg/m2). Plasma NPY, galanin and leptin concentrations were measured by radioimmunoassay. Plasma leptin levels in obese women with PCOS (groups A and B) were significantly higher than those in the control group (p < 0.05, p < 0.05, respectively). A significant positive correlation between plasma leptin and BMI in women with PCOS was found (r = 0.427, p < 0.01). A positive correlation was demonstrated between leptin and testosterone in PCOS (r = 0.461, p < 0.01). Plasma galanin concentrations in PCOS were higher than in the control group but the differences were not significant. Plasma NPY levels were significantly elevated in both non-obese (normal) and obese women with PCOS (group A) (p < 0.01, p < 0.005, respectively). However, in obese non-PCOS women plasma NPY levels gradually increased with increase in BMI. No significant correlations were found between galanin, NPY and percentage change in response of LH to LHRH, as well as between NPY and insulin, and galanin and testosterone. Plasma insulin concentrations in women with PCOS (group B) were significantly higher than in the control group (p < 0.001). Increased plasma NPY levels are found in both obese and non-obese women with PCOS. The increase in NPY is independent of the increase in BMI. In obese women with PCOS, plasma leptin is increased compared with control lean women. Serum insulin concentration is increased in obese women with P

Topics: Adolescent; Adult; Body Mass Index; Estradiol; Female; Follicle Stimulating Hormone; Galanin; Humans; Immunoenzyme Techniques; Insulin; Leptin; Luteinizing Hormone; Neuropeptide Y; Obesity; Polycystic Ovary Syndrome; Prolactin; Radioimmunoassay; Testosterone

The pathogenetic mechanisms behind insulin resistance in polycystic ovary syndrome (PCOS) are far from fully elucidated. Aberrant counterregulatory responses to hypoglycaemia have been reported in patients with insulin resistance, and recent reports suggest that plasma glucose may be regulated at lower levels in women with PCOS. In this study we investigated the complete hormonal counterregulatory response to hypoglycaemia in women with PCOS.. Prospective cross-sectional study.. Eight obese (BMI > or = 25) and 10 non-obese (BMI < 25) women with PCOS, diagnosed by means of ultrasonography and clinical signs of chronic anovulation. Eight obese and 9 non-obese controls.. Hypoglycaemia was induced by an intravenous bolus of soluble insulin (0.15 IU/kg body weight). The counterregulatory responses of cortisol, GH, catecholamines, glucagon, chromogranin A (CGA), and neuropeptide Y (NPY) were studied together with symptoms of hypoglycaemia.. The obese women with PCOS had a more pronounced truncal-abdominal body fat distribution (waist hip ratio, WHR) and were hyperinsulinaemic, compared with the obese controls. All the women exhibited blood glucose levels (< 2 mmol/l) well below the threshold for the hormonal counterregulatory response and for the appearance of clinical symptoms. The non-obese women with PCOS showed a greater increase in serum concentrations of GH than the lean controls. The obese women with PCOS exhibited blunted responses of noradrenaline and NPY, but similar increases of adrenaline and CGA, compared with the obese controls. They also showed a lower symptom score during hypoglycaemia. The response of noradrenaline to hypoglycaemia correlated inversely with fasting insulin levels in the women with PCOS. Among all the obese women (PCOS and controls pooled) basal levels of noradrenaline correlated inversely with the WHR.. All the women with PCOS, independent of BMI, body fat distribution and insulin levels, showed preserved counterregulatory responses to hypoglycaemia. The reduced plasma levels of noradrenaline and the lower perception of hypoglycaemic symptoms in the obese women with PCOS could both reflect a lower activation of the sympathetic nervous system. This aberration seems related to truncal-abdominal obesity and hyperinsulinaemia. The finding of an increased response of GH in the lean women with PCOS could support previous suggestions of an altered activity of the GH/IGF-I system in these women.

Topics: Adult; Body Mass Index; C-Peptide; Chromogranin A; Chromogranins; Cross-Sectional Studies; Female; Growth Hormone; Humans; Hypoglycemia; Insulin; Neuropeptide Y; Norepinephrine; Obesity; Polycystic Ovary Syndrome; Prospective Studies