Acute insulin response to intravenous glucagon in polycystic ovary syndrome

In order to evaluate the acute insulin response after i.v. injection of glucagon in polycystic ovary syndrome (PCOS), 35 women affected by PCOS and 11 normo-ovulatory controls underwent a 75 g oral glucose tolerance test (OGTT) and, 2 days later, a glucagon test (1 mg i.v.). Patients were analysed according to their degree of obesity; the insulin release after glucagon injection for lean PCOS subjects and control women was not statistically significantly different. Conversely obese PCOS patients had higher insulin secretion after both i.v. glucagon and OGTT when compared to the other groups. Moreover the insulin secretory patterns were heterogeneously represented in lean and obese PCOS women. When the patients were analysed according to their insulinaemic response to OGTT, normoinsulinaemic PCOS women and control subjects had a similar insulin response to i.v. glucagon whereas the hyperinsulinaemic PCOS group had a higher insulin response (P < 0.0001). Moreover, a highly significant relationship was found between the insulin response to OGTT and to glucagon administration in the PCOS population (P < 0.0001; r = 0.73), which was maintained also after controlling for obesity. Our results are consistent with the hypothesis that PCOS patients could have an insulin hyper-response to glucagon administration, that is partially independent from obesity and related to their insulinaemic status. Moreover, the glucagon test could represent an effective alternative to OGTT in screening insulin disorders of PCOS patients (at least in the absence of other risk factors), due to its reliability, simplicity, and speed of performance.      

Endocrine and metabolic effects of octreotide, a somatostatin analogue, in lean PCOS patients with either hyperinsulinaemia or lean normoinsulinaemia

The effects on insulin secretion and on the glycaemic and androgen status before and after short-term treatment with octreotide were evaluated in 16 normal weight patients with polycystic ovarian syndrome (PCOS). Hyperinsulinaemia was determined by measuring the insulin response after oral glucose tolerance test (OGTT). Seven patients (group A) were classified as normoinsulinaemic, while nine patients (group B) were considered hyperinsulinaemic according to insulin response after OGTT. Octreotide treatment did not modify either glycaemic or insulinaemic response after OGTT, or androgen profile, in normoinsulinaemic patients. On the contrary, a significant decrease in the basal concentrations of luteinizing hormone (LH), testosterone and androstenedione, and a significant increase in serum concentrations of sex hormone-binding globulin (SHBG) were observed in the hyperinsulinaemic group of patients, in which we observed also a significant decrease of insulinaemic response and a decompensation of the glycaemic profile after OGTT. Our study is the first report showing that: (i) octreotide does not appear to significantly influence pituitary release of gonadotrophins in this group of PCOS patients; (ii) octreotide is able to reduce insulin release, LH and androgen concentrations in lean PCOS patients with hyperinsulinaemia. Due to the presence of a decompensation of glucose homeostasis during treatment, octreotide does not seem advisable for long-term therapy of hyperandrogenism in lean PCOS patients with hyperinsulinaemia.     

Adipocyte resistin mRNA levels are down-regulated by laparoscopic ovarian electrocautery in both obese and lean women with polycystic ovary syndrome

BACKGROUND: The aim of this study was to investigate serum and adipocyte mRNA expression of resistin in lean and obese women with polycystic ovary syndrome (PCOS) before and 3 months after laparoscopic ovarian electrocauterization (LOE). METHODS: Adipose tissue obtained from 12 women with PCOS (six obese and six lean, body mass index > 27 kg m(-1) as threshold point) before and after LOE was analysed. Gene expression of resistin was measured by semi-quantitative RT-PCR. Ten lean, age-matched healthy women served as controls. RESULTS: Both lean and obese women with PCOS had significantly higher fasting and 2 h insulin and homeostasis model insulin resistance index (HOMA(IR)) values and lower fasting glucose-to-insulin ratios (G(0)/I(0)) than did the controls. The serum levels of glucose and insulin and HOMA(IR) were significantly decreased, and the G(0)/I(0) ratio was significantly increased 3 months after LOE. No difference was found in serum resistin levels between controls and either obese or lean women with PCOS before LOE, nor between PCOS patients before and after LOE. However, resistin mRNA expression levels in both lean and obese women with PCOS before LOE were significantly higher than that in controls and were decreased significantly after LOE back to control levels. CONCLUSION: Local resistin activity may be actively involved in the pathogenesis of PCOS. LOE reduces insulin resistance and down-regulates resistin mRNA expression in lean and obese women with PCOS.     

Insulin sensitivity, insulin secretion, and metabolic and hormonal parameters in healthy women and women with polycystic ovarian syndrome

To study the contributions of body mass, body fat distribution and family history of type 2 diabetes mellitus to hyperinsulinaemia, insulin secretion and resistance in polycystic ovarian syndrome (PCOS), 17 lean (LC) and 17 obese (OC) healthy control subjects, and 15 lean (LPCOS) and 28 obese (OPCOS) women with PCOS were investigated. Waist:hip ratio (WHR), serum concentrations of sex steroids, glucose and insulin during a 75 g oral glucose tolerance test (OGTT), and insulin and C-peptide early phase secretion, and insulin sensitivity index using a euglycaemic hyperinsulinaemic clamp were assessed. The PCOS subjects had a higher mean WHR than the controls. A trend towards hyperinsulinaemia and impairment of insulin sensitivity (including the rates of both glucose oxidation and non-oxidation) was observed in LPCOS subjects, but only in OPCOS subjects were these changes significant. Early phase insulin secretion but not the early phase C-peptide secretion was increased in PCOS subjects compared to controls, suggesting that peripheral hyperinsulinaemia in PCOS women was mainly due to the observed lowered hepatic insulin extraction and insulin resistance in skeletal muscle. Moreover, the presence of a family history of type 2 diabetes did not affect early phase insulin or C-peptide secretion in the PCOS group. These results confirm and strengthen earlier contentions, that insulin resistance is a characteristic defect in PCOS and is worsened particularly by abdominal obesity.     

Effect of feeding on growth hormone response to growth hormone-releasing hormone in polycystic ovarian syndrome: relation with body weight and hyperinsulinism

The plasma growth hormone (GH) response to direct stimulation with growth hormone-releasing hormone (GHRH) before and after a standard meal was investigated in 14 polycystic ovarian syndrome (PCOS) subjects. Data were compared with those obtained from 14 healthy normovulatory matched patients. All women underwent an oral glucose tolerance test (OGTT) (75 g) and basal plasma hormone concentrations were evaluated. On a different day all subjects had a GHRH test (50 microg GHRH) both before and after lunch randomly. In obese PCOS subjects the GH response to GHRH was blunted after a meal, while in obese control patients there was an enhanced response of GH to GHRH after a meal. Normal control subjects showed an inhibition of the GH response after feeding and lean PCOS subjects showed a trend toward an augmented GHRH related secretion after a meal significantly higher than normal controls (P < 0.05) but not significantly higher than the pre-prandial response. In conclusion, the data indicate in PCOS a derangement of GH secretion related to food ingestion; in particular obese PCOS patients did not exhibit any change of GH response after a meal compared with the paradoxical response observed in obese controls. Several other factors beyond body mass index and hyperinsulinism could be involved in these pathophysiological events.     

The effects of rosiglitazone and metformin on oxidative stress and homocysteine levels in lean patients with polycystic ovary syndrome

BACKGROUND: Oxidative stress and hyperhomocysteinaemia are risk factors for cardiovascular diseases. The aim of this study was to assess the effects of rosiglitazone and metformin on cardiovascular disease risk factors such as insulin resistance, oxidative stress and homocysteine levels in lean patients with polycystic ovary syndrome (PCOS). METHODS: Fifty lean patients (BMI <25 kg/m2) with PCOS and 35 healthy subjects were included this study. Serum homocysteine, sex steroids, fasting insulin, fasting glucose and lipid levels were measured. Total antioxidant status (TAS; combines concentrations of individual antioxidants) and malonyldialdehyde concentration (MDA) were determined. Insulin resistance was evaluated by using the homeostasis model insulin resistance index (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), Area under the curve insulin (AUCI) and the insulin sensitivity index (ISI). Patients were divided into two groups. One group was treated with metformin (n = 25) and the other received rosiglitazone (n = 25) for 12 weeks. All measurements were repeated at the end of 12 weeks. RESULTS: Compared with healthy women, those with PCOS had significantly elevated serum MDA, homocysteine, HOMA-IR, AUCI and lipoprotein a levels, and significantly decreased serum TAS, QUICKI and ISI. Serum free testosterone levels showed a significant positive correlation with MDA, AUCI and HOMA-IR, and a negative correlation with TAS, ISI and QUICKI in PCOS patients. HOMA-IR and AUCI significantly decreased, while QUICKI and ISI significantly increased after treatment in both groups. Serum TAS level increased and serum MDA level decreased after the rosiglitazone treatment, but these parameters did not change after the metformin treatment. Serum homocysteine and lipid levels did not change in either group, while serum androgen levels and LH/FSH ratio significantly decreased after the treatment period in only the rosiglitazone-treated group. CONCLUSION: Elevated insulin resistance, oxidative stress and plasma homocysteine levels and changes in serum lipid profile (risk factors for cardiovascular disease) were observed in lean PCOS patients. Rosiglitazone seemed to decrease elevated oxidative stress when compared with metformin treatment in lean PCOS patients.     

Patterns of hormonal response to the GnRH agonist leuprolide in brothers of women with polycystic ovary syndrome: a pilot study

BACKGROUND: The aim of this study was to evaluate the effect of a single dose of leuprolide acetate on gonadotrophin and gonadal steroid secretion in brothers of women with polycystic ovary syndrome (PCOS), in order to assess P450c17alpha activity. An oral glucose tolerance test (OGTT) and a lipid profile were also performed. METHODS: Twenty-two unrelated brothers of women with PCOS (PCOS(b)) and 14 brothers of normal cycling women (C(b)), matched for age, underwent a leuprolide acetate test (10 microg/kg s.c.) and an OGTT with measurement of circulating concentrations of gonadotrophins, steroid hormones, glucose, insulin and lipids. RESULTS: Clinical and basal hormonal parameters were similar in both groups. After leuprolide administration, PCOS(b) exhibited a significant increase of 17alpha-hydroxyprogesterone (17-OHP) compared to C(b) (P<0.05). However, only 45% of PCOS(b) showed a supranormal increase of 17-OHP (2 SD above the respective control group mean values, P<0.003) with a normal gonadotrophin response (group 1). The other 55% of the PCOS(b) exhibited a normal 17-OHP response to the analogue (group 2). However, in group 2, basal steroid concentrations did not show a uniform pattern: six of the PCOS(b) exhibited high basal androstenedione (2 SD above the respective control group mean values), three were very similar to C(b), and the other three presented lower basal testosterone concentrations (2 SD below the respective control group mean values) than those observed in C(b). CONCLUSIONS: This study shows that different responses to leuprolide in PCOS brothers make evident the heterogeneity of this syndrome in which P450c17alpha activity could be involved.     

Decreased serum paraoxonase 1 (PON1) activity: an additional risk factor for atherosclerotic heart disease in patients with PCOS?

BACKGROUND: Patients with polycystic ovary syndrome (PCOS) may have an increased risk for the development of hypertension and atherosclerotic heart disease (AHD), the pathophysiological mechanisms of which are not clear. Paraoxonase1 (PON1) is a high-density lipoprotein-associated enzyme that prevents oxidative modification of low-density lipoprotein. The aim of this study was to measure the serum levels of PON1 activity in patients with PCOS and to compare with those of regularly cycling controls. METHODS: Serum lipid parameters, malondialdehyde (MDA) levels and PON1 activity, were measured in PCOS patients (n = 23) and regularly cycling, age-, body mass index- and smoking status-matched controls (n = 23). All patients had normal glucose tolerance test as assessed by a 75 g oral glucose tolerance test. None of the patients had clinically evident hypertension or AHD. RESULTS: Apart from the mean serum PON1 activity, all parameters in the lipid profile including serum MDA levels were comparable between the two groups. There were no significant differences in respect to fasting glucose (4.64 +/- 0.5 versus 4.43 +/- 0.83 mmol/l) and fasting glucose insulin ratio (11.06 +/- 8.26 versus 11.49 +/- 4.90) among the two groups (P > 0.05). However, HOMA insulin resistance index was significantly higher in patients with PCOS compared with the controls (2.06 +/- 0.86 versus 1.51 +/- 0.49; P = 0.01). Also, mean serum PON1 activity was significantly lower in the PCOS group compared with the controls (151.2 +/- 90.8 versus 217.7 +/- 101.6, respectively; P = 0.027). CONCLUSIONS: Reduced serum PON1 activity might contribute to the increased susceptibility for the development of AHD in women with PCOS.     

Dyslipidaemia in poly cystic ovarian syndrome: different groups, different aetiologies?

The objective was to study the pathophysiology of the dyslipidaemiain polycystic ovarian syndrome (PCOS) patients, and to determinehow it is related to hyperinsulin-aemia, hyperandrogenism anddehydroepiandrosterone sulphate (DHEA-S) concentrations. Thelipoprotein lipid profile, anthropometric measurements, endocrineprofile and the presence of insulin resistance were evaluatedin 31 PCOS patients and 20 age-matched healthy women, who servedas controls. PCOS patients had higher fasting insulin concentrations,higher body mass indexes (BMI) and were hyperlipidaemic, withhigher total cholesterol, low density lipoprotein (LDL) andtriglyceride (TG) concentrations. There were no relationshipsbetween plasma lipids and anthropometric variables in the patientgroup as a whole. Insulin-resistant (IR) and non-ER (NIR) PCOSpatients were then evaluated separately. Obesity with markedhyperandrogenism were the predominant features in patients withIR. NIR patients were not obese and had significantly less hyperandrogenism.The adrenal androgen DHEA-S was at the upper limit of its normalrange in both groups. However, both PCOS subgroups exhibitedsimilar significant abnormalities in terms of their lipid parameters.Insulin and DHEA-S concentrations were positively correlatedwith total cholesterol, LDL and TG, and negatively correlatedwith high density lipoprotein, in IR patients. In NIR subjects,insulin was not correlated with any of the lipids and DHEA-Swas negatively related to cholesterol and LDL. Anthropometricvariables were related to lipids in only the NIR patients. ThusPCOS subjects as a group exhibit dyslipidaemia, characterizedby increased total cholesterol, LDL and TG concentrations. Whendivided into IR and NIR subjects, there were no differencesin the degree of lipid abnormalities, despite significant variationsin the BMI and androgen status. Thus, in PCOS subjects, dyslipidaemiamay occur irrespective of insulin resistance. Insulin and DHEA-Sconcentrations were positively correlated with an atherogeniclipid profile in the IR group only. As distinct from syndromeX when IR was present, dyslipidaemia was not related to bodyweight or the waist:hip ratio. In the NTR group there was norelationship between lipids and insulin; DHEA-S, on the otherhand, was negatively related to cholesterol and LDL concentrations.Thus, dyslipidaemla in PCOS patients may occur irrespectiveof insulin resistance, and may have different metabolic aetiologiesdepending on DHEA-S metabolism. It remains to be seen whetherthe two types of PCOS are associated with different risks forischaemic heart disease.     

Effect of ovarian suppression on glucose metabolism of young lean women with and without ovarian hyperandrogenism

Gonadal steroids are believed to influence glucose metabolism, oestrogens inducing an improvement and androgens or progestins a deterioration. At baseline and after 3 months of ovarian suppression with a gonadotrophin-releasing hormone analogue (GnRHa: goserelin depot 3.75 mg/28 days), glucose metabolism was evaluated in eight lean women affected by ovarian hyperandrogenism (PCOS) and six age-weight-matched non-hyperandrogenic women (controls) by using both an oral glucose tolerance test (75 g; OGTT) and the minimal model method. The latter method allows calculation of peripheral insulin sensitivity (Si) and glucose dependent glucose utilization (Sg). In PCOS, higher fasting concentrations (P < 0.05) of insulin and C-peptide, and lower Sg (P < 0.05) and Si (P < 0.01) were found. GnRHa did not significantly modify glucose metabolism of controls, while in women with PCOS it decreased fasting glucose (P < 0.05) and significantly increased Si (P < 0.03) up to control values. The present data indicate that strong suppression of ovarian activity improves Si in lean women with PCOS, while it is without relevant effects on glucose metabolism of non-hyperandrogenic women.     

Rosiglitazone and ethinyl estradiol/cyproterone acetate as single and combined treatment of overweight women with polycystic ovary syndrome and insulin resistance

BACKGROUND: Few studies have evaluated insulin sensitizers in comparison/association with oral contraceptives (OC) in women with polycystic ovary syndrome (PCOS) with insulin resistance (IR). This study assessed the effects of a thiazolidinedione versus an anti-androgenic estrogen-progestin followed by their sequential combinations in overweight PCOS women. METHODS AND RESULTS: Twenty-eight candidates in whom elevated insulin was not normalized after 4 months of diet were randomly assigned to 6 months of rosiglitazone 4 mg/day or to ethinyl estradiol 35 mg/cyproterone acetate 2 mg (EE/CPA: 21/28 days cycle). Each group then received both medications for another 6 months. Rosiglitazone reduced insulin, IR indices [homeostasis model assessment (HOMA) and quantitative sensitivity check index (QUICKI)] and the insulin area under the curve in response to an oral glucose tolerance test (OGTT), but had limited effect on lipids, androgens and hirsutism. EE/CPA did not modify insulin and OGTT response but increased high-density lipoprotein cholesterol and triglycerides and decreased androgens and hirsutism. Similar changes occurred during combined treatments. End results were highly significant in combined groups without noticeable side-effects or changes in safety parameters. CONCLUSIONS: In obese PCOS women with high insulin not corrected by diet, the combination of rosiglitazone and EE/CPA may be used to achieve complementary beneficial effects on endocrine-metabolic anomalies and clinical symptoms.     

Amelioration of insulin resistance in women with PCOS via reduced insulin receptor substrate-1 Ser312 phosphorylation following laparoscopic ovarian electrocautery

BACKGROUND: Increased Ser(312) phosphorylation of insulin receptor substrate (IRS)-1 is one possible molecular mechanism of insulin resistance in polycystic ovary syndrome (PCOS). We investigated whether laparoscopic ovarian electrocautery (LOE) improved insulin sensitivity in women with PCOS and examined the underlying molecular mechanism of LOE. METHODS: Adipose tissue and blood samples from 12 women with PCOS before, and 3 months after, LOE were analysed. RESULTS: Before LOE, women with PCOS were found to have significantly higher 2 h glucose, fasting and 2 h insulin levels, homeostasis model insulin resistance index and lower fasting glucose-to-insulin ratio (G(0)/I(0)) than healthy, lean, age-matched controls. Serum levels of glucose and insulin were significantly decreased, and G(0)/I(0) ratio was significantly increased 3 months after LOE. Levels of activated extracellular signal-regulated kinase 1/2 in PCOS women were higher than in controls, but were significantly decreased after LOE. Levels of insulin receptor, glucose transporter-4 and phosphatidylinositol 3-kinase were lower in PCOS patients before LOE than in controls and increased after LOE. Levels of Ser(312)-phosphorylated IRS-1 in PCOS women before LOE were higher than in controls and decreased significantly after LOE, whereas IRS-1 tyrosine phosphorylation in PCOS women before LOE was lower than in controls and increased significantly after LOE. CONCLUSION: Over the short observation period of this study, our results demonstrated that LOE effectively ameliorated insulin resistance in women with PCOS via decreased IRS-1 Ser(312) phosphorylation.     

Serum visfatin in relation to insulin resistance and markers of hyperandrogenism in lean and obese women with polycystic ovary syndrome

BACKGROUND: Visfatin, a protein secreted by adipose tissue, is suggested to play a role in pathogenesis of insulin resistance. In polycystic ovary syndrome (PCOS), insulin resistance might be involved in the development of endocrine and metabolic abnormalities. The aim of the study was to asses the relation between serum visfatin concentration and insulin sensitivity and markers of hyperandrogenism in lean and obese PCOS patients. METHODS: The study group consisted of 70 women with PCOS (23 lean and 47 obese) and 45 healthy women (25 lean and 20 obese). Euglycemic hyperinsulinemic clamp and the measurements of serum visfatin, sex hormones were performed. RESULTS: The PCOS group had lower insulin sensitivity (P=0.00049) and higher serum visfatin (P=0.047) in comparison to the control group. The decrease in insulin sensitivity was present in both the lean (P=0.019) and obese (P=0.0077) PCOS subjects, whereas increase in serum visfatin was observed only in lean PCOS subjects (P=0.012). In the whole group, serum visfatin was negatively correlated with insulin sensitivity (r=-0.27, P=0.004). This relationship was also observed in the subgroup of lean (r=-0.30, P=0.038), but not obese women. Additionally, in lean women, visfatin was associated with serum testosterone (r=0.47, P=0.002) and free androgen index (r=0.48, P=0.002), independently of other potential confounding factors. CONCLUSIONS: Visfatin is associated with insulin resistance and markers of hyperandrogenism in lean PCOS patients.     

Alterations in cardiac flow parameters in patients with polycystic ovarian syndrome.

The aim of this study was to examine the echocardiographic profiles of patients with polycystic ovarian syndrome (PCOS). Serum concentrations of follicle stimulating hormone, luteinizing hormone, androstenedione, free testosterone, prolactin, DHEA-SO(4) and 17-OH-progesterone, lipid profile (high and low density lipoproteins, triglyceride and total cholesterol) and basal and total insulin after a glucose tolerance test were measured in 35 patients with PCOS and 35 healthy controls matched for body mass index. Doppler, two dimensional M mode echocardiography was performed for the following indices: isovolumetric relaxation time (IVRT), E wave duration time (EVT), A wave duration time (AVT), E wave deceleration time (DT), peak early diastolic flow velocity (PEV), peak late diastolic flow velocity (PAV), E wave velocity time integral (FVI-E), A wave velocity time integral (FVI-A), atrial filling fraction (AFF), ejection fraction (EF), pre-ejection time (PEP), ejection time (ET) and aortic flow velocity time integral (FVI). Androstenedione, free testosterone, low density lipoproteins and cholesterol concentrations were significantly higher in patients with PCOS. There was no difference in basal and total insulin concentrations. IVRT, AVT, FVI-A, AFF, and PEP were higher in patients with PCOS, while PEV, FVI-E, EF, ET, EVT and EVT/AVT were higher in the control group. There was a positive correlation between basal insulin values and IVRT, and between total insulin values and EF. These changes are consistent with a non-restrictive type of diastolic dysfunction and left ventricular stiffness. PCOS may lead to diastolic dysfunction via hyperinsulinaemia and male type dyslipidaemia.     

Serum and adipocyte resistin in polycystic ovary syndrome with insulin resistance

BACKGROUND: The aim of this study was to investigate the relationship between resistin and insulin resistance in patients with polycystic ovary syndrome (PCOS). METHODS: We compared serum resistin levels in 17 PCOS women and 10 lean, healthy, age-matched non-PCOS women and also compared levels of insulin receptor (IR), phosphatidylinositol-3 kinase (PI3-kinase), glucose transporter 4 (GLUT4) protein and resistin mRNA in adipocytes isolated from the omental adipose tissue of five of the PCOS patients and five age- and weight-matched, non-PCOS controls, to look for local defects in insulin action in PCOS. RESULTS: The PCOS group was hyperinsulinaemic and displayed an impaired insulin response in a 75 g oral glucose tolerance test and an abnormal homeostasis model insulin resistance index. Serum resistin levels were similar in PCOS patients and controls; however, resistin mRNA levels were 2-fold higher in adipocytes from PCOS patients. No correlation was found between serum resistin levels and either the BMI or testosterone levels. Western blot analysis showed that adipocyte levels of insulin receptor, PI3-kinase, and GLUT4 were respectively decreased by 56, 39.4 and 54% in PCOS patients compared with controls. CONCLUSIONS: These results suggest that overexpression of the resistin gene in adipocytes may be a local determinant factor in the pathogenesis of PCOS.     

Impact of overnight dexamethasone suppression on the adrenal androgen response to an oral glucose tolerance test in women with and without polycystic ovary syndrome

In order to test the hypothesis that adrenocortical overactivity, possibly related to the stress of testing, may impact on the measurement of circulating androgen concentrations during glucose- induced hyperinsulinaemia, we prospectively screened 10 patients with the polycystic ovary syndrome (PCOS) and nine healthy control women with an oral glucose tolerance test (OGTT), before and after the administration of dexamethasone. Blood sampling was performed at 0, 30, 60, 90, and 120 min following the oral ingestion of 75 g of glucose, before and after the administration of 1.0 mg dexamethasone on the evening prior to testing. Total and free testosterone, androstenedione, dehydroepiandrosterone (DHEA), DHEA sulphate (DHEAS), cortisol, glucose and insulin were assessed during the 2 h OGTT. Women with PCOS had increased basal concentrations of free testosterone, total testosterone, androstenedione, and insulin compared to control women. In women with PCOS an acute decline in circulating concentrations of DHEAS occurred during the OGTT. In PCOS women there were no changes in other ovarian or adrenal androgens during OGTT before or following dexamethasone administration. In control women DHEA concentrations declined during the OGTT. Following overnight dexamethasone suppression in control women, circulating concentrations of DHEAS and testosterone also declined. It is concluded that: (i) in PCOS women only the concentration of circulating DHEAS decreased during glucose-induced hyperinsulinaemia and dexamethasone administration did not further alter androgen responses to an OGTT; (ii) it is possible that, in these hyperandrogenic patients, the insulin-related suppression of adrenocortical testosterone and DHEA is negated by their much greater ovarian secretion of these androgens; (iii) in control women DHEA concentrations acutely declined during the OGTT and the administration of dexamethasone resulted in the acute decline of DHEA, DHEAS, and testosterone; (iv) it appears that the stress related to testing impacts on the androgen response to OGTT, at least in healthy women.      

Polymorphisms in the insulin receptor substrate-1 (IRS-1) gene and the insulin receptor substrate-2 (IRS-2) gene influence glucose homeostasis and body mass index in women with polycystic ovary syndrome and non-hyperandrogenic controls

BACKGROUND: We aimed to evaluate the influence of the Gly972Arg variant of the insulin receptor substrate-1 gene (IRS-1) and the Gly1057Asp variant in IRS-2 on insulin resistance and glucose tolerance in women with polycystic ovary syndrome (PCOS) and healthy controls. METHODS: Genotypes, allelic frequencies, indexes of insulin resistance, glucose tolerance and hormone profiles were studied in a large sample of Spanish PCOS (n = 103) women compared with a control group (n = 48) of healthy women matched for body mass index. RESULTS: No differences in genotype or allelic frequencies were found between PCOS patients and healthy controls. When considering control subjects and PCOS patients as a whole, IRS-1 Arg972 carriers also presented with increased fasting insulin (133 +/- 60 versus 95 +/- 67 pmol/l, P = 0.008) and insulin resistance measured by homeostasis model assessment (4.3 +/- 2.1 versus 3.1 +/- 2.4, P = 0.009) compared with subjects homozygous for Gly972 alleles. These differences were even higher when restricting the analysis to PCOS patients. Subjects homozygous for the Gly1057 allele of IRS-2 presented with increased 60 and 90 min oral glucose tolerance test (OGTT) glucose levels compared with carriers of one or two Asp1057 alleles (7.9 +/- 2.1 versus 7.1 +/- 2.1 mmol/l, P = 0.042 and 7.0 +/- 2.1 versus 6.0 +/- 1.8 mmol/l, P = 0.014), and a similar tendency was observed for 120 min OGTT glucose levels. CONCLUSIONS: The Gly972Arg in IRS-1 and Gly1057Asp in IRS-2 polymorphisms influence glucose homeostasis in premenopausal women, but are not associated with PCOS.     

Early impaired ��-cell function in chinese women with polycystic ovary syndrome

Background: The pathogenic factors that account for the development of diabetes condition in Chinese women with polycystic ovary syndrome (PCOS) remain elusive. Aim: To clarify the pathogenic features by evaluating the levels of insulin sensitivity and β cell function in these women with PCOS, either separately or by using of a disposition indexes (DIs). Methods: Cross-sectional study involving 137 Chinese women with PCOS and 123 normal women were examined by anthropometry, lipid profile, sex hormone, high-sensitivity C reactive protein, oral glucose tolerance tests and insulin tolerance tests. Results: After controlling for BMI status, the Matsuda Index was significantly lower in women with PCOS in comparison to those of normal women (p<0.000). The early phase of insulin secretion (insulinogenic index) remained significantly lower in lean women with PCOS(LP) than those of both lean and obese women of control group (p=0.007, and p = 0.01, respectively). The mean HOMA-F values were significantly lower (p =0.045) in obese women with PCOS (OP) than those of BMI-matched women. Further, all DIs derived from non-fasting state indexes in women with PCOS were significantly lower than those of BMI-matched control women (p<0.001 for all). Lastly, DIs derived from fasting states indexes in OP were significantly lower than those of LP. Conclusion: Early impaired β cell function was detected in both LP and OP. However, more serious primary defect in insulin action was detected in LP compared to OP. These findings imply that early screening and intervention for PCOS would be therapeutic for Chinese women.     

Leptin concentrations in hirsute women with polycystic ovary syndrome or idiopathic hirsutism: influence on LH and relationship with hormonal, metabolic, and anthropometric measurements.

BACKGROUND: The known association between leptin, obesity and insulin action suggests that leptin may have a role in polycystic ovarian syndrome (PCOS) but this has only been addressed peripherally. METHODS: We assessed the influence of leptin on LH and investigated the relationship between leptin and body mass index (BMI), waist:hip ratio (WHR), androgen concentrations, fasting insulin and insulin:glucose ratio (IGR) in 27 women with PCOS and in 20 age- and weight-matched women with regular, ovulatory menstrual cycles and idiopathic hirsutism (IH). RESULTS: Leptin concentrations were significantly higher in obese PCOS women than in normal weight women with either PCOS or IH (P = 0.0028), but did not differ between obese women with PCOS and IH. WHR, insulin concentrations and IGR were significantly higher in obese PCOS patients in comparison with the three other groups. In IH patients, the association between leptin concentrations and WHR was lost after adjustment for BMI. In PCOS patients, a significant correlation was observed between leptin and fasting insulin concentrations, IGR, WHR and LH. After adjustment for BMI, only the correlation with LH remained significant. A stepwise regression model was set up with LH as the dependent variable to test the hypothesis that the concentrations of leptin might be modulating the concentrations of LH in PCOS patients. The relationship of LH concentrations with IGR was found to be BMI dependent. In contrast, leptin concentrations contributed negatively and significantly to LH concentrations, independently of either BMI or IGR. CONCLUSIONS: We speculate that the known attenuation in basal or stimulated response of LH in obese PCOS patients might be related to leptin resistance, which could influence LH hypersecretion. In IH ovulatory patients, normal LH concentrations suggest the presence of preserved regulatory mechanisms of GnRH pulsatility. Further studies are needed to specifically investigate the proposed correlation between leptin and GnRH modulation in PCOS.     

Effect of pioglitazone treatment on the adrenal androgen response to corticotrophin in obese patients with polycystic ovary syndrome

BACKGROUND: To investigate the effect of pioglitazone on adrenal steroidogenesis in polycystic ovary syndrome (PCOS), we studied 11 obese (two with BMI >25 kg/m(2); nine with BMI >27 kg/m(2)) PCOS women before and after 6 months of treatment at a dose of 45 mg/day. METHODS: During the early follicular phase, ultrasonography and hormonal assays were performed. On separate days, all women underwent an oral glucose tolerance test (OGTT), a euglycaemic hyperinsulinaemic clamp and an adrenocorticotrophin hormone (ACTH) test. The same protocol was repeated after therapy. RESULTS: Pioglitazone treatment significantly reduced the insulin response to OGTT and improved the insulin sensitivity indices (P < 0.01 and P = 0.03 respectively). A significant decrease was found in LH (P < 0.05) and androstenedione (P < 0.01) levels after therapy, whereas the other hormonal parameters improved but not significantly. Pioglitazone administration reduced the response of 17alpha-hydroxyprogesterone (17OHP) and androstenedione to ACTH (P < 0.01 and P < 0.02 respectively), most likely through an inhibition of cytochrome P450. The same treatment was able to rebalance the relative activity of 17,20-lyase, as documented by an increase in the androstenedione:17OHP ratio (P < 0.05) after ACTH stimulation. CONCLUSIONS: Our data support the contention that insulin enhances ACTH-stimulated steroidogenesis, while inducing a relative impairment of 17,20-lyase activity. Whether the beneficial effects of pioglitazone on this imbalance could be related to the ameliorated glyco-insulinaemic metabolism or to a direct effect on the adrenal glands remains to be determined.