Effects of metformin treatment in women with polycystic ovary syndrome depends on insulin resistance

The identification and functional analysis of CircRNAs in endometrial receptivity of mice with polycystic ovary

The disorders of endometrial receptivity and ovulatory dysfunction are both significant causes of infertility in patients with polycystic ovary syndrome (PCOS). In this study, we investigated the expression profile and functional implications of circular RNAs (circRNAs) in the endometrial receptivity of PCOS-affected mice. Twenty-four female C57BL/6 mice were divided into PCOS and normal control groups. The PCOS group received subcutaneous DHEA treatment, while the control group remained untreated. Gene chip technology was utilized to analyze circRNA expression in endometrial tissues on the fourth day of gestation with subsequent bioinformatics analyses into circRNA functions. Furthermore, endometrial epithelial cells were used to determine represented circRNA functions. Results showed that the PCOS group exhibited 205 differentially expressed circRNAs, with 147 upregulated and 58 downregulated ones. qRT-PCR confirmed differential expression of circRNAs, including circRNA_38548, circRNA_001686, circRNA_38550, and circRNA_27938. Predicted target genes and a circRNA-miRNA-mRNA regulatory network were constructed. Additionally, four circRNAs (circRNA_38548, circRNA_38550, and circRNA_001686) were identified to contribute to abnormal endometrial receptivity by regulating genes such as Lifr, FOXK1, FOXO1, HOXA10, through interactions with miRNAs. Further research is warranted to elucidate the underlying mechanisms involving these circRNAs.

Comprehensive Management of Polycystic Ovary Syndrome: Effect of Pharmacotherapy, Lifestyle Modification, and Enhanced Adherence Counseling

Introduction Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of childbearing age in India, which often presents as menstrual irregularities, infertility, acanthosis nigricans, etc. Metabolic disturbances associated with PCOS predispose patients to cardiovascular diseases, which may be avoided by effective management. The aim of the current study was to evaluate the role of lifestyle modification (LSM) and metformin in PCOS management. Methods This is a retrospective cohort study conducted among 130 PCOS patients who attended the outpatient department of the tertiary care hospital in central India from October 2019 to March 2020. The study describes the effect of a combined package of LSM (physical exercise and dietary changes) and metformin on anthropometric, clinical, and biochemical parameters at three and six months. Results Out of the total 130 women, 12 were lost to follow-up and were omitted from further analysis. At six months of the treatment package (LSM, metformin, and enhanced adherence counseling (EAC)), a significant decrease was seen in body mass index, blood sugar, follicle-stimulating hormone, luteinizing hormone, and insulin. Following the intervention, the menstruation cycle became regular in 91% of the women while volume, theca, and appearance of polycystic ovaries on ultrasound decreased in 86% of women. Insulin resistance (IR) and hyperinsulinemia are the major causes of pathophysiological changes associated with PCOS. Metformin along with LSM primarily acts by decreasing IR, while EAC ensures treatment compliance. Conclusion Metformin along with LSM in the form of calories restricted, high-protein diet, and physical activity reduce IR and hyperandrogenaemia, resulting in improved anthropometric, glycemic indices, hormonal profiles, and features of hyperandrogenaemia. The combined therapy is beneficial to 85-90% of women with PCOS.

Metformin effects on zonulin level in polycystic ovarian women

Zonulin protein is a haptoglobin precursor and functions to modulate the permeability of tight junctions between enterocytes. Local inflammation or systemic inflammation can trigger zonulin expression. While the increased zonulin level causes an increase of intestinal permeability and entrance of foreign antigens, the latter can increase insulin resistance and inflammation. Polycystic ovarian syndrome affects women during their reproductive age characterized by hyperinsulinemia and/or hyperandrogenemia and associated with infertility problems. Changes in gut permeability such as irritable bowel syndrome are often found in PCOS patients. While metformin increases insulin mediates glucose uptake and, acts as an insulin-sensitizing drug used to treat PCOS patients is recently discovered to reshape intestinal bacteria and hence may affect intestinal action. This study was designed to find any association between zonulin level and other parameters in PCOS patients and to find metformin treatment effects on zonulin in PCOS patients. Thirty-one newly diagnosed PCOS women agree to take metformin 850 mg twice daily for three months and, and to give fasting serum samples to measure zonulin, FSH, LH, total testosterone, free testosterone, SHBG, fasting insulin, and fasting serum glucose before and after treatment. The free testosterone and zonulin are determined by the ELISA technique while the other parameters are determined by the Cobas technique. According to patients' Homeostatic Model Assessment (HOMA-IR), the Patients were divided into two sub-groups: the first group consisting of those with initial HOMA-IR less than two and the second group was those of an initial HOMA-IR of between two to four. Whereas the first group showed no significant response to treatment, the second group showed a better response to metformin treatment, as demonstrated by their LH, total testosterone, free testosterone, fasting insulin, zonulin, and glucose levels. These parameters markedly improved after metformin treatment with p-values of 0.08, 0.09, 0.07. 0.04, 0.01 and 0.06, respectively.

Resistance to the Insulin and Elevated Level of Androgen: A Major Cause of Polycystic Ovary Syndrome

PCOS has a wide range of negative impacts on women's health and is one of the most frequent reproductive systemic endocrine disorders. PCOS has complex characteristics and symptom heterogeneity due to the several pathways that are involved in the infection and the absence of a comm14on cause. A recent study has shown that the main etiology and endocrine aspects of PCOS are the increased level of androgen, which is also known as "hyperandrogenemia (HA)" and secondly the "insulin resistance (IR)". The major underlying cause of the polycystic ovary is these two IR and HA, by initiating the disease and its severity or duration. As a consequence, study on Pathogenesis is crucial to understand the effect of "HA" and "IR" on the pathophysiology of numerous symptoms linked to PCOS. A deep understanding of the pattern of the growth in PCOS for HA and IR can help ameliorate the condition, along with adjustments in nutrition and life, as well as the discovery of new medicinal products. However, further research is required to clarify the mutual role of IR and HA on PCOS development.

The Efficacy of 24-Month Metformin for Improving Menses, Hormones, and Metabolic Profiles in Polycystic Ovary Syndrome

CONTEXT

The long-term effects of metformin in women with polycystic ovarian syndrome (PCOS) are inadequately studied.

OBJECTIVE

The effects of metformin on women with PCOS during 24 months with respect to menses, hormones, and metabolic profiles are assessed.

DESIGN

Prospective cohort.

SETTING

A reproductive endocrinology clinic in a university-affiliated medical center.

PATIENTS

One hundred nineteen women with PCOS, defined by the Rotterdam criteria, were enrolled.

INTERVENTION

Metformin was given daily for 24 months.

MAIN OUTCOME MEASURES

The primary outcome was the proportion of patients with regular menstruation during treatment. Changes in anthropometric, hormonal, and metabolic parameters were also assessed. Analyses were performed using segmented regression analysis with a generalized estimating equation methodology. Outcomes are expressed as magnitude of change from the baseline.

RESULTS

Both overweight (OW) and normal-weight (NW) women with PCOS had increased menstrual frequency and decreased body mass index (BMI), testosterone, and luteinizing hormone levels in the first 6 months. Further stratification showed that NW women exhibiting elevated testosterone at baseline had the largest magnitude of improvement at 6 months [odds ratio (OR), 7.21; 95% confidence interval (CI), 2.35 to 22.17], whereas OW patients with normal testosterone were most likely to achieve normal menses at 12 months (OR, 0.63; 95% CI, 0.47 to 0.77).

CONCLUSIONS

Metformin was associated with improvements in the menstrual cycle and most hormonal profiles in OW and NW women with PCOS during 24 months of treatment. Most parameters reached maximal response and steady-state after 6 months. Phenotypic differences in baseline BMI and testosterone level can be used as patient selection criteria or treatment prognostics.

Protective effects of GABA against metabolic and reproductive disturbances in letrozole induced polycystic ovarian syndrome in rats

Background

PCOs is a heterogeneous disorder with anovulation/oligo ovulation usually taken as oligo menorrhoea or amenorrhoea, hyperandrogenemia, hirsutism, acne, androgen alopecia and polycystic ovaries as the key diagnostic feathers. The study was undertaken to investigate the possible protective and ameliorating effects of GABA in Letrozole induced PCOS model in rats by targeting insulin resistance.

Methods

PCOs in Adult female rat was induced by the daily gastric administration of letrozole (1 mg/kg/day) in CMC (0.5%) for 36 days. Rats were given metformin (2 mg/kg), GABA (100 mg/kg/day) and GABA (500 mg/kg/day) along with letrozole. One group severed as vehicle control. On the 37 day, the animals were euthanized, and anthropometrical, biochemical (glucose, insulin, lipids, testosterone, Estradiol, Progesterone, oral glucose tolerance test, total protein content in ovary, cholesterol level, triglyceride, HDL, LDL), Antioxidants (CAT, POD, GSR, ROS, GSH, TBARS), and histopathological evaluation of ovaries were carried out. Daily colpocytological examination was also carried out until the termination.

Results

Both the doses of GABA significantly reduced body weight, body mass index and testosterone. While the levels of CAT, SOD, POD and Estradiol (E₂) were significantly increased in the both doses of GABA. A favourable lipid profile, normal glucose tolerance, and decreased in the percentage of estrus smears were observed. Histopathological examination of ovary revealed a decreased in the number of cystic follicles, and decreased in the adipocytes respectively. The effects observed with GABA were comparable to that with metformin.

Conclusion

The results suggest that GABA treatment has shown protective effect in PCOs and provide beneficial effect either by reducing insulin resistance or by inducing antioxidant defence mechanisms.

Ameliorative effects of rutin against metabolic, biochemical and hormonal disturbances in polycystic ovary syndrome in rats

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most prevalent endocrinopathy in women of reproductive age. The study was commenced to assess the favorable effects of Rutin against metabolic, biochemical, histological, and androgenic aspects of polycystic ovary syndrome in rats.

METHODS

Female Sprague-Dawley rats were administered letrozole (1 mg/kg) per orally (p.o) for a period of 21 days for the induction of PCOS, followed by dose of rutin (100 mg/kg and 150 mg/kg, p.o) for 15 days using 0.5% w/v CMC as vehicle. Metformin was also given as a standard control to one of the rat groups. Serum estradiol, progesterone, testosterone, serum lipid parameters, CRP and glucose levels were evaluated. Furthermore, antioxidant activity was tested using superoxide dismutase, catalase, glutathione per-oxidase and reactive-oxygen species level.

RESULTS

Rutin flavonoid had a dose-dependent effect on androgenic levels depicting more recovery in the rutin-I treated group, while rutin-II treated groups showed better antioxidant and lipid profiles as compared with PCOS groups. A decrease in the value of C reactive protein (CRP) and a restoration in the proportion of estrous phase smears were observed in the rutin treated groups. Histopathological examination of ovary revealed a significant decrease in the number of cystic follicles in post treated groups. The effects observed with rutin were moderately similar to that with standard metformin, a widely used treatment drug for PCOS.

CONCLUSION

The study provides evidence for the potential ameliorative effects of rutin against clinical and biochemical features of PCOS.

A Dietary Medium-Chain Fatty Acid, Decanoic Acid, Inhibits Recruitment of Nur77 to the HSD3B2 Promoter In Vitro and Reverses Endocrine and Metabolic Abnormalities in a Rat Model of Polycystic Ovary Syndrome

Hyperandrogenism is the central feature of polycystic ovary syndrome (PCOS). Due to the intricate relationship between hyperandrogenism and insulin resistance in PCOS, 50%-70% of these patients also present with hyperinsulinemia. Metformin, an insulin sensitizer, has been used to reduce insulin resistance and improve fertility in women with PCOS. In previous work, we have noted that a dietary medium-chain fatty acid, decanoic acid (DA), improves glucose tolerance and lipid profile in a mouse model of diabetes. Here, we report for the first time that DA, like metformin, inhibits androgen biosynthesis in NCI-H295R steroidogenic cells by regulating the enzyme 3β-hydroxysteroid dehydrogenase/Δ5-Δ4-isomerase type 2 (HSD3B2). The inhibitory effect on HSD3B2 and androgen production required cAMP stimulation, suggesting a mechanistic action via the cAMP-stimulated pathway. Specifically, both DA and metformin reduced cAMP-enhanced recruitment of the orphan nuclear receptor Nur77 to the HSD3B2 promoter, coupled with decreased transcription and protein expression of HSD3B2. In a letrozole-induced PCOS rat model, treatment with DA or metformin reduced serum-free testosterone, lowered fasting insulin, and restored estrous cyclicity. In addition, DA treatment lowered serum total testosterone and decreased HSD3B2 protein expression in the adrenals and ovaries. We conclude that DA inhibits androgen biosynthesis via mechanisms resulting in the suppression of HSD3B2 expression, an effect consistently observed both in vitro and in vivo. The efficacy of DA in reversing the endocrine and metabolic abnormalities of the letrozole-induced PCOS rat model are promising, raising the possibility that diets including DA could be beneficial for the management of both hyperandrogenism and insulin resistance in PCOS.

High-visfatin levels in women with polycystic ovary syndrome: evidence from a meta-analysis

OBJECTIVE

Previous studies regarding visfatin levels in women with polycystic ovary syndrome (PCOS) showed conflicting results. To evaluate the visfatin levels in PCOS, a meta-analysis was performed.

METHODS

A comprehensive literature search of eligible studies in Embase, Pubmed and the Cochrane Library was undertaken through November 2014. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated to estimate the strength of the association.

RESULTS

A total of 1341 subjects (695 cases and 646 controls) were included in this meta-analysis. The pooled analysis results indicated that the visfatin levels were significantly higher in PCOS patients than that of controls (SMD = 1.19, 95% CI 0.77-1.60, p = 0.000). The results from stratified analysis and univariate analysis suggested that high-visfatin levels were not related to body mass index (BMI), insulin resistance (IR) and total testosterone ratio. Significant heterogeneity was observed in all analysis.

CONCLUSION

Our results indicate that high-circulating visfatin level is an intrinsic characteristic of PCOS, which suggests visfatin could be a potential biomarker for PCOS.

Leutinizing hormone/choriogonadotropin receptor and follicle stimulating hormone receptor gene variants in polycystic ovary syndrome

PURPOSE

Previous studies identified follicle-stimulating hormone receptor (FSHR) and luteinizing hormone/choriogonadotropin receptor (LHCGR) genes as polycystic ovary syndrome (PCOS) susceptibility loci, which was dependent on the racial/ethnic background of studied population. We investigated the association of genetic variants in FSHR and LHCGR with PCOS in Bahraini Arab women.

METHODS

A retrospective case-control study, involving 203 women with PCOS, and 211 age- and ethnically-matched control women. FSHR and LHCGR genotyping was done by allelic exclusion method (real-time PCR).

RESULTS

Significantly lower frequencies of heterozygous LHCGR rs7371084 and FSHR rs11692782 genotype carriers were seen between women with PCOS vs. controls, and increased frequency of heterozygous homozygous LHCGR rs4953616 genotype carriers were detected between women with PCOS compared to control women. Limited linkage disequilibrium was noted among LHCGR and FSHR SNPs, and 2 blocks were constructed: the first (Block 1) spanning 61 kb contained the six tested LHCGR SNPs, and the second (Block 2) spanning 298 kb contained four of the five tested FSHR SNPs. Higher frequency of LHCGR GTCAAG haplotype was seen in women with PCOS compared to controls; the frequencies of the remaining LHCGR haplotypes, and all FSHR haplotypes were similar between cases and controls.

CONCLUSION

This is the first study to confirm the association of novel LHCGR (rs7371084, rs4953616) and FSHR (rs11692782) SNPs with PCOS. The differential association of LHCGR and FSHR variants with PCOS confirms the racial/ethnic contribution to their association with PCOS.

The Role of Metformin in Metabolic Disturbances during Pregnancy: Polycystic Ovary Syndrome and Gestational Diabetes Mellitus

Maintenance of gestation implicates complex function of multiple endocrine mechanisms, and disruptions of the global metabolic environment prompt profound consequences on fetomaternal well-being during pregnancy and postpartum. Polycystic Ovary Syndrome (PCOS) and gestational diabetes mellitus (GDM) are very frequent conditions which increase risk for pregnancy complications, including early pregnancy loss, pregnancy-induced hypertensive disorders, and preterm labor, among many others. Insulin resistance (IR) plays a pivotal role in the pathogenesis of both PCOS and GDM, representing an important therapeutic target, with metformin being the most widely prescribed insulin-sensitizing antidiabetic drug. Although traditional views neglect use of oral antidiabetic agents during pregnancy, increasing evidence of safety during gestation has led to metformin now being recognized as a valuable tool in prevention of IR-related pregnancy complications and management of GDM. Metformin has been demonstrated to reduce rates of early pregnancy loss and onset of GDM in women with PCOS, and it appears to offer better metabolic control than insulin and other oral antidiabetic drugs during pregnancy. This review aims to summarize key aspects of current evidence concerning molecular and epidemiological knowledge on metformin use during pregnancy in the setting of PCOS and GDM.

Effect of metformin and spironolactone therapy on OGTT in patients with polycystic ovarian syndrome - a retrospective analysis

BACKGROUND

Metformin (an insulin sensitizer) and spironolactone (an antiandrogen) are both used for treatment of polycystic ovary syndrome. We analyzed the effect of 6 months of therapy with these drugs on body weight and glucose tolerance.

RESULTS

This was a retrospective analysis of polycystic ovarian syndrome (PCOS) cases on treatment. There were 88 patients with PCOS-42 were on metformin 1 g daily and 46 were taking spironolactone 50-75 mg daily. 21 of 42 had abnormal glucose tolerance (AGT) in the metformin group and 13 of 46 had AGT in the spironolactone group. Patients on metformin reported a greater reduction in body weight, whereas there was no change in body weight with spironolactone therapy (67.6-63.7 versus 59.6-59.2 kg). There was a significant reduction in the 1 and 2 h glucose and insulin levels with metformin therapy in those with AGT. However, fasting glucose increased in those with normal glucose tolerance. There was no change in either body weight or insulin levels with spironolactone. But, there was a significant reduction in both the 0 and 2 h glucose with spironolactone also in those with AGT.

CONCLUSION

Spironolactone and metformin had similar effect in reducing the glucose levels in PCOS patients with AGT. PCOS patients with normal glucose tolerance had higher fasting plasma glucose at the end of 6 months of metformin therapy inspite of weight reduction.

Insulin and hyperandrogenism in women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a very common endocrine disorder characterized by chronic anovulation, clinical and/or biochemical hyperandrogenism, and/or polycystic ovaries. But most experts consider that hyperandrogenism is the main characteristic of PCOS. Several theories propose different mechanisms to explain PCOS manifestations: (1) a primary enzymatic default in the ovarian and/or adrenal steroidogenesis; (2) an impairment in gonadotropin releasing hormone (GnRH) secretion that promotes luteal hormone (LH) secretion; or (3) alterations in insulin actions that lead to insulin resistance with compensatory hyperinsulinemia. However, in the past 20 years there has been growing evidence supporting that defects in insulin actions or in the insulin signalling pathways are central in the pathogenesis of the syndrome. Indeed, most women with PCOS are metabolically insulin resistant, in part due to genetic predisposition and in part secondary to obesity. But some women with typical PCOS do not display insulin resistance, which supports the hypothesis of a genetic predisposition specific to PCOS that would be revealed by the development of insulin resistance and compensatory hyperinsulinemia in most, but not all, women with PCOS. However, these hypotheses are not yet appropriately confirmed, and more research is still needed to unravel the true pathogenesis underlying this syndrome. The present review thus aims at discussing new concepts and findings regarding insulin actions in PCOS women and how it is related to hyperandrogenemia.

Metformin, naltrexone, or the combination of prednisolone and antiandrogenic oral contraceptives as first-line therapy in hyperinsulinemic women with polycystic ovary syndrome

To compare the short-term effects of metformin (M), naltrexone (N), and a combination of OC and prednisolone (OC/Pr) on the metabolic state and the ovarian function of PCOS women, we randomized 29 women to a 3-month course of therapy. We observed significant improvements in hyperandrogenemia and ovulation rates in PCOS women of all three groups, in the absence of changes in the metabolic state, suggesting that insulin resistance in PCOS patients is only one of several factors leading to hyperandrogenemic ovarian failure.

Evidence-based and potential benefits of metformin in the polycystic ovary syndrome: a comprehensive review

Metformin is an insulin sensitizer widely used for the treatment of patients affected by type 2 diabetes mellitus. Because many women with polycystic ovary syndrome (PCOS) are insulin resistant, metformin was introduced in clinical practice to treat these patients also. Moreover, metformin's effect has other targets beside its insulin-sensitizing action. The present review was aimed at describing all evidence-based and potential uses of metformin in PCOS patients. In particular, we will analyze the uses of metformin not only for the treatment of all PCOS-related disturbances such as menstrual disorders, anovulatory infertility, increased abortion, or complicated pregnancy risk, hyperandrogenism, endometrial, metabolic and cardiovascular abnormalities, but also for the prevention of the syndrome.

Effect of metformin on serum visfatin levels in patients with polycystic ovary syndrome

OBJECTIVE

To evaluate serum visfatin levels and to determine the effects of metformin treatment on visfatin levels in patients with polycystic ovary syndrome (PCOS).

DESIGN

Cross-sectional study.

SETTING

University hospital.

PATIENT(S)

Nineteen patients with PCOS and 21 controls.

INTERVENTION(S)

Metformin was given to patients with PCOS, and serum visfatin levels were measured before and after treatment.

MAIN OUTCOME MEASURE(S)

Glucose, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, DHEAS, total T, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), and visfatin levels were measured.

RESULT(S)

Serum visfatin levels were significantly higher in women with PCOS than in controls. Visfatin could differentiate between women with and without increased diabetogenic risk at a cut-off value of 19.24 ng/mL, with a sensitivity of 93.3% and a specificity of 84%. In bivariate analysis of subjects, T, insulin, and waist circumference were significantly and positively correlated with visfatin. Treatment resulted in a significant decrease in body mass index and a decrease in visfatin concentration. After therapy, statistically significant decreases in HOMA-IR, fasting insulin, free T, and DHEAS concentrations were observed for the PCOS group.

CONCLUSION(S)

Circulating visfatin levels were higher in patients with PCOS than healthy controls, and metformin treatment significantly reduced circulating visfatin concentrations after 3 months of therapy.

Use of metformin in polycystic ovary syndrome

Women with polycystic ovary syndrome (PCOS) have a myriad of phenotypic and clinical features that may guide therapeutic options for metabolic protection and ovulation induction. The use of metformin may prove beneficial in a subset of the population of women with PCOS. Hyperinsulinemia, as demonstrated by elevated insulin levels on a 2-hour 75-g load glucose tolerance test, is an important parameter in deciding whether or not to initiate metformin therapy to women with PCOS with the hope of preventing or delaying the onset of type 2 diabetes mellitus (DM). Cardiovascular risk factors including markers of subclinical inflammation, and dyslipidemia may also be improved by metformin therapy. For ovulation induction, metformin is not as effective as clomiphene citrate as first-line therapy for women with PCOS. There are no clear data to suggest that metformin reduces pregnancy loss or improves pregnancy outcome in PCOS, and it is currently recommended that metformin be discontinued with the first positive pregnancy test result, unless there are other medical indications (eg, type 2 DM). This review addresses practical management guidelines for the uses of metformin in women with PCOS.

Evidence for insulin suppression of baseline luteinizing hormone in women with polycystic ovarian syndrome and normal women

CONTEXT

In women with polycystic ovarian syndrome (PCOS), the relationship of insulin to LH secretion and responses to GnRH remains unresolved. A rigorous analytical examination of this relationship has not been performed.

OBJECTIVE

Our objective was to determine the relationship of basal LH secretion and responses to GnRH, insulin, and other endocrine variables in normal and PCOS women.

DESIGN

In PCOS and normal women, mean composite 12-h LH secretion was analyzed for correlating factors. LH responses to varying doses of GnRH during a fixed rate of insulin infusion and LH responses to a fixed dose of GnRH during varying doses of insulin infusion were analyzed for contributing factors.

PATIENTS AND SETTING

Eighteen PCOS and 21 normal women underwent studies of frequent blood sampling and GnRH stimulation before and during insulin infusion at the General Clinical Research Center, University of California, San Diego.

MAIN OUTCOME MEASURES

Group mean composite 12-h LH levels were assessed with respect to other endocrine variables. In addition, LH responses to GnRH with or without insulin infusion were assessed.

RESULTS

In normal women, insulin negatively predicted mean LH. In PCOS, the combined effect of body mass index (negative) and testosterone (positive) predicted LH. The best predictor of LH was body mass index and insulin combined. Basal LH and LH responses to GnRH were unaltered by insulin infusion in normal women. These measures were reduced during insulin infusion in PCOS women.

CONCLUSIONS

In PCOS, insulin infusion suppresses pituitary response to GnRH. In normal women, insulin negatively correlates with mean LH and suppresses GnRH response at a high infusion rate.

Impact of metformin and rosiglitazone treatment on glucose transporter 4 mRNA expression in women with polycystic ovary syndrome

OBJECTIVE

The insulin-resistant state of the polycystic ovary syndrome (PCOS) was found to be associated with a decreased glucose transporter GLUT4 expression in the insulin target tissues. This study was performed to explore whether the well-known clinical, hormonal and metabolic efficacy of metformin or rosiglitazone treatment is reflected in the modulation of adipocyte GLUT4 mRNA expression in patients with PCOS.

METHODS

We enrolled 35 women with PCOS. They received either metformin or rosiglitazone for 6 months. A history, blood samples for the measurement of androgens and s.c. adipose tissue samples were taken at baseline and end point. Quantification of GLUT4 mRNA expression in adipose tissue was performed using real-time quantitative PCR. Homeostasis model assessment (HOMA(IR)) score calculation was applied as a measure for insulin resistance (IR).

RESULTS

GLUT4 mRNA expression in adipose tissue increased significantly in both groups (P<0.001). The increase was more pronounced in the rosiglitazone group (P=0.040). There was a statistically significant improvement of HOMA(IR) in both groups (P=0.008). After treatment, frequencies of menstrual bleeding were significantly higher (P<0.001) and serum total testosterone levels significantly lower in both groups (P=0.001).

CONCLUSIONS

A 6-month therapy with insulin sensitizers resulted in marked improvement in adipose tissue GLUT4 mRNA expression in PCOS patients, rosiglitazone being more effective when compared with metformin. The augmentation of the insulin signal transduction was accompanied by a significant improvement of HOMA(IR), menstrual pattern and androgen profile.