Increased activation of nuclear factor kappaB triggers inflammation and insulin resistance in polycystic ovary syndrome

CONTEXT: Insulin resistance and chronic low level inflammation are often present in women with polycystic ovary syndrome (PCOS). OBJECTIVE: The purpose of this study was to determine the effects of hyperglycemia on nuclear factor kappaB (NFkappaB) activation and inhibitory kappaB (IkappaB) from mononuclear cells (MNC) in PCOS. DESIGN AND SETTING: This was a prospective controlled study conducted at an academic medical center. PATIENTS: The study population consisted of 16 reproductive-age women with PCOS (eight lean, eight obese) and 16 age- and body composition-matched controls (eight lean, eight obese). MAIN OUTCOME MEASURES: Insulin sensitivity (IS) was derived from a 2-h 75-g oral glucose tolerance test (IS(OGTT)). Intranuclear NFkappaB and IkappaB protein expression were quantitated from MNC obtained from blood drawn fasting and 2 h after glucose ingestion. RESULTS: IS(OGTT) was lower in PCOS compared with controls (3.3 +/- 0.3 vs. 6.4 +/- 0.9, P < 0.004). The percent change in intranuclear NFkappaB was higher in lean and obese PCOS compared with lean controls (42.5 +/- 19.1 and 54.5 +/- 12.5 vs. -14.1 +/- 10.9, P < 0.006). The percent change in intranuclear NFkappaB correlated positively with 2-h post-glucose ingestion levels (r = 0.37; P < 0.04) and plasma testosterone (r = 0.49; P < 0.006) and correlated negatively with IS(OGTT) (r = 0.39; P < 0.04). The percent change in IkappaB was lower in lean and obese PCOS compared with lean controls (-22.3 +/- 3.2 and -17.0 +/- 5.0 vs. 8.4 +/- 11.8, P < 0.02). CONCLUSION: In response to hyperglycemia, intranuclear NFkappaB increases and IkappaB decreases in MNC of women with PCOS independent of obesity. This may represent a cardinal inflammatory signal that contributes to the induction of insulin resistance and hyperandrogenism in PCOS.     

The correlation of plasma omentin-1 with insulin resistance in non-obese polycystic ovary syndrome

ObjectivesAberrant circulating adipokines are considered to be related to the pathological mechanism of polycystic ovary syndrome (PCOS). This study aims to evaluate the relationship between plasma omentin-1 levels, metabolic and hormonal parameters in the setting of non-obese Chinese women with PCOS.Material and methodsThis was a case-controlled, cross-sectional study of 153 non-obese (BMI < 25 kg/m²) PCOS and 114 age-matched healthy non-obese control individuals. Levels of plasma omentin-1, fasting blood glucose, insulin and sexual hormones and ovary volume were analyzed in all subjects.ResultsPlasma omentin-1 levels of non-obese PCOS individuals were significantly lower than in healthy non-obese controls. Body Mass Index (BMI), homeostasis model of assessment for insulin resistance index (HOMA-IR), levels of testosterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), LH/FSH ratio and ovary volume (OV) were significantly higher in subjects with PCOS than controls. In the HOMA-IR stratified subgroups, PCOS individuals with insulin resistance had lower omentin-1 than those without insulin resistance after BMI adjustment. Omentin-1 was negatively correlated with BMI, HOMA-IR and fasting insulin. Multiple linear regressions revealed that BMI contributed to omentin-1 levels. Ovary volume was negatively correlated to HOMA-IR but had no correlation with omentin-1.ConclusionsPlasma omentin-1 concentrations were decreased in the non-obese PCOS group. Insulin resistance could further decrease plasma omentin-1 in non-obese individuals with PCOS independent of BMI status.     

Total ghrelin levels during acute insulin infusion in patients with polycystic ovary syndrome

Controversial data were reported concerning fasting ghrelin (decreased, normal or elevated) in polycystic ovary syndrome (PCOS). The aim of our study was to clarify ghrelin levels in non-obese, overweight, and obese PCOS patients; to investigate the effect of acute insulin infusion on ghrelin in PCOS as a chronic insulin-resistant state, with and without the impact of obesity, and to examine ghrelin-androgen interaction. In that order, we evaluated 1) ghrelin levels among 8 nonobese patients with PCOS [body mass index (BMI): 20.52+/-1.31 kg/m2], 8 overweight and obese patients with PCOS (BMI: 34.36+/-6.53 kg/m2) and their respective controls, 2) ghrelin suppression during euglycemic hyperinsulinemic clamp, and 3) ghrelin-androgen interrelationship. After overnight fast, 2-h euglycemic hyperinsulinemic clamp, was performed in all investigated women. Fasting ghrelin was significantly lower in non-obese PCOS than in controls (64.74+/-25.69 vs 108.36+/-52.60; p<0.05) as well as in overweight and obese PCOS in comparison with controls (38.71+/-14.18 vs 98.77+/-40.49; p<0.05). Insulin infusion significantly suppressed ghrelin in all subgroups of investigated women. Analysis of variance for repeatable measures confirmed that there was no significant difference in pattern of response between PCOS and controls. In conclusion, women with PCOS had lower fasting ghrelin and decreased insulin sensitivity independently of their BMI, compared to the controls. In addition, there were no differences between fasting ghrelin levels among non-obese, overweight, and obese women with PCOS. During euglycemic hyperinsulinemic clamp, ghrelin decreased in all studied groups to a similar extent, implying that, compared to chronic hyperinsulinemia, acute hyperinsulinemia reduces ghrelin levels independently of the degree of insulin resistance.     

The metabolic syndrome in young Korean women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is characterized by insulin resistance and consequent hyperinsulinemia. Insulin resistance also plays an important role in the metabolic syndrome (MS). We conducted a cross-sectional study to determine the prevalence of the MS in young Korean women with PCOS and whether it is associated insulin resistance. One hundred and seventeen young women with PCOS (age: 26+/-5, 16-39 years) were evaluated for the frequency of MS according to the modified Adult Treatment Panel III. Total testosterone (T), free T, androstenedione, dehydroepiandrosterone sulfate (DHEAS) and sex hormone binding globulin (SHBG) were measured, and insulin sensitivity was evaluated by euglycemic hyperinsulinemic clamp technique. The prevalence of MS in women with PCOS was 14.5%, nearly 3.5-fold higher than in age-matched women in Korean urban population (4.3%) [J.-Y. Oh, Y.-A. Sung, Y.S. Hong, E. Barrett-Conner, Prevalence and factor analysis of metabolic syndrome in an urban Korean population, Diabetes Care 27 (2004) 2027-2032]. The most frequently occurring component of MS was low HDL cholesterol (45%), and the least frequent was high fasting serum glucose level (0.9%). PCOS women with MS had significantly higher free T, and lower SHBG compared with those without MS. And women with MS showed significantly lower M-value and higher fasting/post-glucose load insulin levels. M-value was still significantly lower in women with MS even after the adjustment for BMI. MS is frequent in young Korean women with PCOS and it reflects more severe insulin resistance. These results suggest the importance of early and regular screening of metabolic disturbance in even young women with PCOS.     

Elevated fasting insulin is associated with cardiovascular and metabolic risk in women with polycystic ovary syndrome

AimsPCOS is associated with various immediate and long term health complications. The aim of this study was to investigate the association of serum fasting insulin concentration with cardiovascular and metabolic risk factors in women with polycystic ovary syndrome.MethodsA total of 349 women, 249 women with polycystic ovary syndrome and 100 age-matched healthy controls, were recruited in this case-control study. Fasting insulin and various other biochemical, hormonal and clinical parameters were measured in all participants. The correlation of insulin with cardiometabolic risk factors was evaluated in PCOS women with normal and high serum insulin concentration.ResultsFasting Insulin, BMI, WHR, FAI, LH: FSH, HOMA, QUICKI were significantly higher in PCOS women compared with healthy controls (p < 0.01). Fasting insulin showed a positive correlation with more cardiovascular and metabolic risk factors in PCOS compared to controls. The BMI, BAI, LAP, HOMA IR, QUICKI and FAI were significantly higher (all p < 0.05) in PCOS patients with higher insulin levels than with PCOS women with normal levels.ConclusionFasting insulin is an important determinant in the pathogenesis of obesity and hyperandrogenism in PCOS. It is associated with an increased risk of cardiovascular and metabolic disorders in women with PCOS.     

多囊卵巢综合征患者血清对氧磷酯酶1活性、氧化应激与胰岛素抵抗的关系

目的探讨对氧磷酯酶1（PON-1）活性、氧化应激在多囊卵巢综合征（PCOS）患者发生胰岛素抵抗（IR）中的作用。方法41例PCOS患者分为肥胖组17例和非肥胖组24例,另有20名健康女性纳入正常对照组。所有研究对象均行口服糖耐量试验（OGTT）和胰岛素释放试验,使用稳态模型评价IR及胰岛B细胞分泌功能,空腹静脉取血检测丙二醛（MDA）、超氧化物歧化酶（SOD）活性及PON-1活性。结果（1）PCOS非肥胖组和PCOS肥胖组的空腹胰岛素、餐后2小时血糖及胰岛素、HOMA—IR及HOMA-β均高于正常组（P〈0．05）,且PCOS肥胖组的空腹胰岛素、餐后2小时血糖及胰岛素、HOMA—IR均高于PCOS非肥胖组（P％0．05）。（2）PCOS非肥胖组和PCOS肥胖组的MDA、SOD及PON-1与正常组比较差异有统计学意义（P〈0．05）;PCOS肥胖组的SOD显著低于PCOS非肥胖组（P％0．01）,而MDA及PON-1两组之间差异无统计学意义（P〉0．05）。（3）相关分析显示：在PCOS非肥胖组,SOD与PON—1正相关（r=0．417,P〈0．05）,SOD与IR负相关（r=0．492,P〈0．05）。结论PCOS患者无论肥胖与否,均存在餐后血糖升高、PON-1活性降低、氧化应激、IR,且肥胖患者更为严重;PCOS患者的氧化应激与IR相关。     

In vitro evidence that hyperglycemia stimulates tumor necrosis factor-alpha release in obese women with polycystic ovary syndrome

Women with polycystic ovary syndrome (PCOS) are often insulin resistant and have chronic low-level inflammation. The purpose of this study was to determine the effects of hyperglycemia in vitro on tumor necrosis factor (TNF)-alpha release from mononuclear cells (MNC) in PCOS. Twelve reproductive-age women with PCOS (six lean, six obese) and 12 age-matched controls (six lean, six obese) were studied. Insulin sensitivity (IS(HOMA)) was estimated from fasting levels of glucose and insulin and percent truncal fat was determined by dual energy absorptiometry (DEXA). TNFalpha release was measured from MNC cultured under euglycemic and hyperglycemic conditions. IS(HOMA) was higher in obese women with PCOS than in lean women with PCOS (student's t-test; 73.7 +/- 14.8 vs 43.1 +/- 8.6, P < 0.05), but similar to that of obese controls. IS(HOMA) was positively correlated with percent truncal fat (r=0.57, P < 0.04). Obese women with PCOS exhibited an increase in the percent change in TNFalpha release from MNC in response to hyperglycemia compared with obese controls (10 mM, 649 +/- 208% vs 133 +/- 30%, P < 0.003; 15 mM, 799 +/- 347% vs 183 +/- 59%, P < 0.04). The TNFalpha response directly correlated with percent truncal fat (r=0.45, P < 0.03) and IS(HOMA) (r=0.40, P < 0.05) for the combined groups, and with plasma testosterone (r=0.60, P < 0.05) for women with PCOS. MNC of obese women with PCOS exhibit an increased TNFalpha response to in vitro physiologic hyperglycemia. MNC-derived TNFalpha release may contribute to insulin resistance and hyperandrogenism, particularly when the combination of PCOS and increased adiposity is present.     

The counterregulatory response to hypoglycaemia in women with the polycystic ovary syndrome

OBJECTIVE 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. DESIGN Prospective cross-sectional study. PATIENTS Eight obese (BMI 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. MEASUREMENTS 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. RESULTS 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. CONCLUSIONS 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.     

Polymorphism of glycogen synthetase gene in polycystic ovary syndrome

OBJECTIVE Polycystic ovary syndrome is a heterogeneous disorder associated with a moderate degree of insulin resistance and a higher risk of developing NIDDM. The exact mechanism of insulin resistance is unclear. This study examines the frequency of an Xbal polymorphism of the glycogen synthetase gene (A2 allele) as a marker of insulin resistance and seeks to relate the presence of the A2 allele to indices of insulin sensitivity in women with polycystic ovary syndrome (PCOS). METHODS Insulin sensitivity was assessed by fasting insulin measurements, as well as following oral glucose tolerance test. An i.v. insulin tolerance test was performed to measure the rate of endogenous blood glucose disposal following an i.v. bolus of insulin. Restriction fragment length polymorphism was performed with Xbal digestion of PCR amplified product to detect the presence of A1 and A2 allele. PATIENTS Seventy-one obese (BMI > 25.1) and 19 non-obese (BMI < 25) women with PCOS, and 62 controls (33 obese and 29 non-obese) participated in the study. RESULTS Obese PCOS had significantly higher fasting insulin ( P = 0.002) compared to obese controls. There was no difference between non-obese PCOS and controls. Twenty per cent of obese PCOS had impaired glucose tolerance. The A1A2 genotype was detected in 16 of the 150 (10.7%) subjects examined. Of these, 11/88 (12.5%) were PCOS and 5/62 (8%) were controls. The A2A2 genotype was not present in any of the subjects. The A1A2 genotype was not detected in any of the subjects with impaired glucose tolerance. There was no significant difference in the incidence of the A1A2 genotype between PCOS and controls or between the individual groups. There was no association between the presence of the A1A2 genotype and indices of insulin sensitivity. CONCLUSION The Xbal polymorphism (A2 allele) of the glycogen synthetase gene was not over represented in the PCOS subject and did not relate to the indices of insulin sensitivity or glucose intolerance.     

Adiponectin is independently associated with insulin sensitivity in women with polycystic ovary syndrome

OBJECTIVE: The polycystic ovary syndrome (PCOS) is associated with obesity and insulin resistance predisposing to diabetes mellitus type 2 and atherosclerosis. Adiponectin is a recently discovered adipocytokine with insulin-sensitizing and putative antiatherosclerotic properties. The aim of the study was to elucidate determinants of circulating adiponectin levels and to investigate the potential role of adiponectin in insulin resistance in PCOS women. PATIENTS AND MEASUREMENTS: Plasma adiponectin and parameters of obesity, insulin resistance and hyperandrogenism were measured In 62 women with PCOS and in 35 healthy female controls. RESULTS: Both in PCOS and controls, adiponectin levels were lower in overweight or obese women than in normal-weight women, without any difference between PCOS and controls after adjustment for body mass index (BMI). In PCOS and in controls there was a significant correlation of adiponectin with BMI (r = -0.516, P < 0.001), fasting insulin (r = -0.404, P < 0.001), homeostasis model sensitivity (HOMA %S) (r = -0.424, P < 0.001) and testosterone (r = -0.279, P < 0.01), but no correlation with androstenedione (r = -0.112, P = 0.325), 17-OH-progesterone (r =-0.031, P = 0.784) or the LH/FSH ratio (r =-0.033, P = 0.753). Multiple linear regression analysis revealed that BMI and HOMA %S but not testosterone were independently associated with adiponectin plasma levels, explaining 16% (BMI) and 13% (HOMA %S) of the variability of adiponectin, respectively. In PCOS patients insulin sensitivity, as indicated by continuous infusion of glucose with model assessment (CIGMA %S) was significantly correlated with adiponectin (r = 0.55; P < 0.001), BMI (r =-0.575; P < 0.001), waist-to-hip ratio (WHR) (r =-0.48; P = 0.001), body fat mass assessed by dual-energy X-ray-absorptiometry (DEXA) [Dexa-fat (total) (r = -0.61; P < 0.001) and Dexa-fat (trunk) (r = -0.59; P < 0.001)] and with testosterone (r = -0.42; P = 0.001). Multiple linear regression analysis demonstrated that markers of obesity such as BMI, total or truncal fat mass, age and adiponectin were independently associated with CIGMA %S, and that circulating adiponectin accounted for about 18% of the degree of insulin resistance in PCOS. By contrast, testosterone was not a significant factor, suggesting that PCOS per se did not affect insulin sensitivity independent from obesity, age and adiponectin. Metformin treatment for 6 months in insulin-resistant PCOS women (n = 9) had no effect on plasma adiponectin (P = 0.59) despite significant loss of weight and fat mass and improvement in hyperandrogenaemia. CONCLUSIONS: PCOS per se is not associated with decreased levels of plasma adiponectin. However, circulating adiponectin is independently associated with the degree of insulin resistance in PCOS women and may contribute to the development and/or maintenance of insulin resistance independent from adiposity.     

Influence of insulin treatment on insulin sensitivity in insulin requiring type 2 diabetes patients

Insulin resistance in type 2 diabetes subjects was investigated before and 6 months after insulin administration in 43 type 2 diabetes patients (28 females and 15 males). Their age was 56.1+/-8.6 years, diabetes duration 11.7+/-6.8 years, BMI 29.5+/-5.3 kg/m2. All patients were on maximal dosage of oral hypoglycaemic agents and had poor metabolic control (HbA1c 11.2+/-1.6%). Insulin sensitivity was measured by euglycaemic clamp (insulin infusion rate 1 mU kg-1 min-1). The glucose disposal rate (M-value) was considerably lower in patients (2.4+/-1.6 mg kg-1 min-1, 0.2-8.1) compared with healthy subjects (7.1+/-0.2 mg kg-1 min-1, p<0.01). M-value was strongly associated with WHR (r=-0.41, p<0.05). The patients with poorest insulin sensitivity had the highest level of total cholesterol (r=-0.41, p=0.02) and LDL-cholesterol (r=-0.38, p=0.03). After 6 months of insulin treatment BMI was 30.3+/-4.2 kg/m2 (p<0.05), mean weight increase was 2.7+/-0.8 kg. M-value was substantially increased to 4.5+/-2.3 mg kg-1 min-1 (p<0.001), the degree of improvement depended on basal insulin sensitivity (r=-0.55, p<0.01). HbA1c was reduced to 7.7+/-1.4% (p<0.01), the correlation M-value with change of HbA1c (r=-0.59, p<0.01) was shown. Total cholesterol decreased from 6.3+/-1.1 to 5.4+/-1.1 mmol/l, LDL-cholesterol from 4.1+/-1.1 to 3.4+/-1.0 mmol/l, triglycerides from 2.6+/-1.6 to 1.6+/-0.7 mmol/l (p<0.001). In conclusion, insulin treatment of type 2 diabetes patients leads to decrease in insulin resistance due to reduction in glucose toxicity and plasma atherogenicity despite weight gain.     

Reactive oxygen species-induced oxidative stress in the development of insulin resistance and hyperandrogenism in polycystic ovary syndrome

CONTEXT: Insulin resistance and chronic low level inflammation are often present in women with polycystic ovary syndrome (PCOS). OBJECTIVE: The purpose of this study was to determine the effects of hyperglycemia on reactive oxygen species (ROS) generation from mononuclear cells (MNCs) in PCOS. DESIGN: This was a prospective controlled study. SETTING: The study was conducted at an academic medical center. PATIENTS: The study population consisted of 16 women with PCOS (eight lean, eight obese) and 15 age- and body composition-matched controls (eight lean, seven obese). MAIN OUTCOME MEASURES: Insulin sensitivity was derived from a 2-h, 75-g oral glucose tolerance test (IS(OGTT)). ROS generation and p47(phox) protein expression were quantitated from MNCs obtained from blood drawn fasting and 2 h after glucose ingestion. RESULTS: IS(OGTT) was lower in PCOS, compared with controls (3.1 +/- 0.3 vs. 6.3 +/- 0.9, P < 0.003). The percent change in ROS generation from MNCs was higher in lean and obese PCOS, compared with lean controls (138.8 +/- 21.3 and 154.2 +/- 49.1 vs. 0.6 +/- 12.7, P < 0.003). The percent change in ROS generation from MNCs correlated positively with glucose area under the curve (r = 0.38, P < 0.05), and plasma levels of testosterone (r = 0.59, P < 0.002) and androstenedione (r = 0.50, P < 0.009). The percent change in p47(phox) from MNCs was also higher in lean and obese PCOS, compared with lean controls (36.2 +/- 18.2 and 39.1 +/- 8.0 vs. -13.7 +/- 8.7, P < 0.02), and correlated negatively with IS(OGTT) (r = -0.39, P < 0.05). CONCLUSION: ROS generation from MNCs in response to hyperglycemia is increased in PCOS independent of obesity. The resultant oxidative stress may contribute to a proinflammatory state that induces insulin resistance and hyperandrogenism in women with this disorder.     

Presence of metabolic risk factors in non-obese PCOS sisters: evidence of heritability of insulin resistance

This study was performed to determine whether phenotypically healthy sisters of women with polycystic ovary syndrome (PCOS) have evidence of insulin resistance. We studied 54 women: 17 with PCOS, 17 sisters of these probands and 20 control women with similar age, body mass index (BMI) and waist-to-hip ratio (WHR). The PCOS sisters had neither clinical nor laboratory evidence of hyperandrogenism. However, estimated insulin resistance indices indicated decreased insulin sensitivity in PCOS sisters compared with the controls. No difference of insulin resistance indices was detected between the PCOS and their sisters. This finding provides additional evidence that there is a hereditary trait regarding insulin resistance in the PCOS families.     

The impact of intensified exercise training on insulin resistance and fitness in overweight and obese women with and without polycystic ovary syndrome

Objective To evaluate mechanisms of insulin resistance (IR) in overweight and obese women with and without polycystic ovary syndrome (PCOS) and explore relationships between IR, fitness and body mass index (BMI) at baseline and following exercise intervention. Design Prospective controlled intensified exercise intervention study. Patients A total of 20 overweight (BMI > 25 kg/m²) and obese (>30 kg/m²), reproductive‐aged PCOS women and 13 non‐PCOS overweight, healthy controls of comparable BMI and age were studied at baseline. Measures were repeated in 13 PCOS and eight control women following three 1‐h exercise sessions per week over 12 weeks. Measurements Insulin resistance was measured by glucose infusion rate on euglycaemic hyperinsulinaemic clamp, and fitness was assessed by VO_2max. Results At baseline, PCOS women were 46% more insulin resistant than controls (175·6 vs 257·2 mg/m²/min, P < 0·05) with IR independently associated with VO_2max and BMI in the PCOS group only (P < 0·01). Postexercise IR improved across both groups (P < 0·01). In PCOS women, IR improved by 16% (P < 0·05) but was not restored to the same level as controls (P < 0·05). Improvement in IR and in VO_2max was related to the PCOS group (r² = 0·85, P < 0·05), yet change in IR and in fitness was not related. No associations were found in controls. Conclusions While intensified exercise improves IR in PCOS women, a higher IR persisted following exercise in PCOS women, and a clear relationship between improved IR and improved fitness was not found. Therefore, other mechanisms of, and therapies for, IR must be explored in PCOS as IR remains higher than observed in non‐PCOS controls.     

Overexpression of the phosphoprotein enriched in diabetes gene product (Ped/pea-15) in women with polycystic ovary syndrome

OBJECTIVE: To evaluate Ped/pea-15 (phosphoprotein enriched in diabetes) expression in polycystic ovary syndrome (PCOS) women. DESIGN AND PATIENTS: Thirty PCOS women were studied and compared with other 30 age- and body mass index (BMI)-matched women, considered as the control group. Both patients and controls were divided according to BMI. All subjects underwent endocrine and metabolic investigation and Ped/pea-15 expression was evaluated by western blot analysis. Insulin resistance was assessed by HOMA model and insulin sensitivity index (ISI) composite. RESULTS: Insulin resistance, evaluated by HOMA-R and ISI composite, was significantly higher in PCOS women and in obese controls than in normal weight controls. Ped/pea-15 expression (%) was higher in PCOS women than in controls (440.4 +/- 220.7 vs. 163.0 +/- 45.5; P < 0.001; range 145.5-987% and 97-281%, respectively), and was positively correlated with insulin, BMI, total testosterone, HOMA index, and family history (P < 0.001). In patients with PCOS univariate analysis of variance showed no effect of BMI variation (P = 0.13) on Ped/pea-15 expression levels. On multiple linear regression analysis, the major determinants of Ped/pea-15 overexpression were family history, insulin, and PCOS status independent of BMI. CONCLUSION: These preliminary data (1) highlight the overexpression of Ped/pea-15 in PCOS compared to normal controls, independent of obesity; (2) suggest that Ped/pea-15 overexpression might be an early component of the metabolic syndrome in PCOS; and (3) support the hypothesis that Ped/pea-15 represents a possible useful tool to assess the presence of a genetic condition associated with insulin resistance in PCOS.     

Is hyperprolactinemia associated with insulin resistance in non-obese patients with polycystic ovary syndrome?

Insulin resistance is common in polycystic ovary syndrome (PCOS). Moderate elevations in serum PRL concentration may contribute to insulin resistance in PCOS. The aim of this study was to determine PRL on development of insulin resistance in non-obese hyperprolactinemic patients with PCOS. Ninety-eight non-obese subjects with PCOS and 100 non-obese healthy control were accepted in the study. Serum glucose, lipids, androgens, free androgen index (FAI), gonadotropins, fat mass and percentage, SHBG, and insulin levels were measured. Homeostasis model assessment (HOMA) was used as index of pancreatic beta-cell function and tissue insulin sensitivity. Independent t-test was used in comparison of results. In patients with PCOS, FAI and mean HOMA-(%B) level were higher than in the control group (p<0.0001), whereas mean HOMA-(%S) in subjects with PCOS was lower than in the control group (p<0.0001). Patients with PCOS were divided into subgroups according to their serum prolactin level (< 24 or > or = 24 ng/ml). Although FAI was not different, mean insulin and HOMA-(%B) levels in hyperprolactinemic patients were higher than in normoprolactinemic subjects (p<0.001). HOMA-(%S) in hyperprolactinemic patients with PCOS was lower than in normoprolactinemic patients (p<0.002). In conclusion, PCOS is associated with insulin resistance; non-obese hyperprolactinemic PCOS patients may be more insulin-resistant than normoprolactinemics and there may be an association between hyperprolactinemia and insulin resistance in PCOS.     

多囊卵巢综合征妇女的β-3-肾上腺素能受体基因与胰岛素抵抗的关系

目的探讨β     

Differential effects of insulin sensitivity on androgens in obese women with polycystic ovary syndrome or normal ovulation

The differential effects of insulin sensitivity and adiposity on androgen concentrations in women with polycystic ovary syndrome (PCOS) are unclear. To address this issue, we divided 43 overweight women into 4 groups based on both their clinical classification (PCOS or normal) and whether they were insulin resistant (IR) or insulin sensitive (IS) by their steady-state plasma glucose concentrations. Total testosterone concentrations were significantly increased as a function of both clinical classification (PCOS vs normal, P < .0001) and steady-state plasma glucose concentration (IR vs IS, P = .002). Mean testosterone concentrations were higher in PCOS-IR compared with PCOS-IS, normal-IR, or normal-IS women (P < .005). In addition, there was a statistically significant interaction (P = .03) between clinical classification (PCOS vs normal) and insulin sensitivity (IR vs IS) for testosterone concentrations. In contrast, androstenedione concentrations were higher in women with PCOS (P = .001), irrespective of whether they were IR or IS (P = .31); and no interaction between clinical classification and insulin sensitivity was discerned (P = .34). These results indicate that both PCOS and insulin resistance independently contributed to increased total testosterone concentrations within a group of overweight/obese women. These findings are consistent with the hypothesis that the ovaries of women with PCOS are hypersensitive to the ability of insulin to increase testosterone production and that the more insulin resistant the patient, the higher the testosterone concentration. In contrast, androstenedione concentrations seem to be independent of differences in insulin resistance. Our findings emphasize the need to increase understanding of the factors that modulate ovarian androgen secretion.     

Polycystic ovary syndrome, metabolic syndrome, cardiovascular risk and the role of insulin sensitizing agents

The Polycystic Ovary Syndrome (PCOS) affects 6 to 10% of women of childbearing age. Insulin resistance and hyperinsulinemia are present in nearly all PCOS patients and play a central role in the development of both hyperandrogenism and metabolic syndrome (MS). MS occurs in approximately 43% of PCOS patients, raising the cardiovascular risk to up seven fold in these patients. Several serum, functional and structural markers of endothelial dysfunction and subclinical atherosclerosis were described in PCOS patients, even those young and non-obese. However, despite the fact that PCOS adversely affects the cardiovascular profile, long-term studies did not demonstrate a consistent raise in cardiovascular mortality, which seems to be more observed in the post-menopausal period. Recently, oral contraceptives are being substituted for insulin sensitizing agents (metformin and glitazones) in the PCOS treatment, due to their effects on insulin resistance and cardiovascular risk.     

Retinol-binding protein 4 levels are elevated in polycystic ovary syndrome women with obesity and impaired glucose metabolism

OBJECTIVE: Insulin resistance and obesity are common features of the polycystic ovary syndrome (PCOS). Retinol-binding protein 4 (RBP4), a new fat-derived adipokine, has been described to be elevated in obesity and type 2 diabetes. The aim of the present study was to investigate whether serum RBP4 levels are correlated with metabolic parameters, indices of insulin resistance, and endocrine variables in German PCOS women. DESIGN: We assessed the correlation between metabolic and endocrine parameters with RBP4 levels in 200 PCOS patients and 64 healthy controls. METHODS: Serum RBP4 was measured by enzyme-linked immunosorbent assay (Immundiagnostik AG, Bensheim, Germany). In addition, anthropometric variables, clinical signs of hyperandrogenism, and body fat were evaluated, and a glucose tolerance test was performed to assess parameters of insulin resistance and glucose metabolism. RESULTS: Taking the entire PCOS cohort, RBP4 levels were positively correlated with body mass index (BMI), body fat, waist circumference, fasting glucose, and area under the curve for glucose (all P<0.05), but not with indices of insulin resistance. On the other hand, PCOS women with impaired glucose metabolism had higher RBP4 levels than PCOS women with normal glucose metabolism (median 30.6, range 23.3-73.9 versus median 26.3, range 6.4-61.4, P<0.05). Furthermore, no differences were found in RBP4 levels between lean PCOS women and BMI-matched healthy controls. CONCLUSION: In German PCOS women, serum RBP4 levels are associated with obesity and parameters of glucose metabolism but not with PCOS per se.