Metformin administration modulates neurosteroids secretion in non-obese amenorrhoic patients with polycystic ovary syndrome

Examining the clinical relevance of metformin as an antioxidant intervention

In physiological concentrations, reactive oxygen species play a vital role in regulating cell signaling and gene expression. Nevertheless, oxidative stress is implicated in the pathogenesis of numerous diseases and can inflict damage on diverse cell types and tissues. Thus, understanding the factors that mitigate the deleterious effects of oxidative stress is imperative for identifying new therapeutic targets. In light of the absence of direct treatment recommendations for reducing oxidative stress, there is a continuing need for fundamental research that utilizes innovative therapeutic approaches. Metformin, known for its multifaceted beneficial properties, is acknowledged for its ability to counteract the adverse effects of increased oxidative stress at both molecular and cellular levels. In this review, we delve into recent insights regarding metformin's antioxidant attributes, aiming to expand its clinical applicability. Our review proposes that metformin holds promise as a potential adjunctive therapy for various diseases, given its modulation of oxidative stress characteristics and regulation of diverse metabolic pathways. These pathways include lipid metabolism, hormone synthesis, and immunological responses, all of which may experience dysregulation in disease states, contributing to increased oxidative stress. Furthermore, our review introduces potential novel metformin-based interventions that may merit consideration in future research. Nevertheless, the necessity for clinical trials involving this drug remains imperative, as they are essential for establishing therapeutic dosages and addressing challenges associated with dose-dependent effects.

Superior mesenteric ganglion neural modulation of ovarian angiogenesis, apoptosis and proliferation by the neuroactive steroid allopregnanolone

Allopregnanolone (ALLO), a potent neuroactive steroid, is synthesized and active in the peripheral nervous system. Previous studies have shown that ALLO participates in the central regulation of reproduction with effects on ovarian physiology, although there is little evidence for its ability to modulate peripheral tissues. The present study aimed to determine whether ALLO, administered to an ex vivo system that comprises the superior mesenteric ganglion (SMG), the ovarian nervous plexus (ONP) and the ovary (O), or to the denervated ovary (DO), was able to modify ovarian apoptosis, proliferation and angiogenesis. For this purpose, the SMG-ONP-O system and DO were incubated during 120 min at 37°C, in the presence of two ALLO doses (0.06 µm and 6 µm). The intrinsic and extrinsic pathways of apoptosis were analyzed. Incubation of the SMG-ONP-O system with ALLO 0.06 µm led to an increase in the BAX/BCL-2 ratio and a reduction of FAS-L mRNA levels. ALLO 6 µm induced a decrease of FAS-L levels. Incubation of DO with ALLO 0.06 µm reduced FAS-L, whereas ALLO 6 µm significantly increased it. Cyclin D1 mRNA was measured to evaluate proliferation. Treatment with ALLO 6 µm increased proliferation in both SMG-ONP-O and DO. ALLO 0.06 µm produced an increase of Cyclin D1 in DO only. Administration of either ALLO dose led to a higher ovarian expression of vascular endothelial growth factor in the SMG-ONP-O system, but a lower one in the DO system. ALLO 6 µm induced ovarian sensitization to GABA by increasing GABA_A receptor expression. In conclusion, ALLO participates in the peripheral neural modulation of ovarian physiology. It can also interact directly with the ovarian tissue, modulating key mechanisms involved in normal and pathological processes in a dose-dependent manner.

Effect of Allopregnanolone on Spatial Memory and Synaptic Proteins in Animal Model of Metabolic Syndrome

Metabolic Syndrome (MetS) is considered a common disorder, especially with a sedentary lifestyle and unhealthy food consumption. Cognitive impairment is one of the MetS consequences that worsens the quality of life of the patients. The study aimed to assess the therapeutic effect of the neurosteroid Allopregnalonone on spatial memory and, therefore, the expression of two synaptic plasticity markers in the hippocampus. Thirty-two male rats were divided into four groups: control groups, MetS, and MetS + Allopregnalone. Spatial memory has been evaluated by the Y-maze task and blood pressure measured by the rat tail method. Biochemical evaluation of serum glucose, insulin, lipid profile, and hippocampal expression of Synaptophysin and Associated Protein 43 (GAP-43) were performed for assessing Allopregnanolone on serum and hippocampal markers. Allopregnanolone therapy improved working spatial memory, hypertension, and biochemical markers measured in the serum and hippocampus.

Polycystic Ovary Syndrome, Affective Symptoms, and Neuroactive Steroids: a Focus on Allopregnanolone

PURPOSE OF REVIEW

To provide an overview of existing studies on alterations in gonadal and neuroactive steroids (NASs) and mood symptoms among women with polycystic ovary syndrome (PCOS).

RECENT FINDINGS

Recent studies have demonstrated a previously underappreciated association between PCOS and comorbid depression and anxiety. However, most studies on affective symptoms among women with PCOS have been cross-sectional, limiting our knowledge about fluctuations in symptoms over the menstrual cycle and reproductive lifespan for women with PCOS, as well as the potential interplay between NAS alterations and mood symptoms. Changes in the NAS allopregnanolone (ALLO) have been implicated in several reproductive-related psychiatric disorders (e.g., premenstrual dysphoric disorder (PMDD) and postpartum depression (PPD)) as well as in normal reproductive functioning, warranting further investigation for its potential role in the psychiatric symptoms observed in women with PCOS. Prospective studies evaluating associations between psychiatric symptoms and NAS are needed to elucidate the biological causes of the increased rates of psychiatric symptoms among women with PCOS and inform clinical treatment. ALLO, with its role in normal reproductive function, menstrual dysregulation among women with PCOS, and reproductive-related psychiatric conditions, makes it a particularly intriguing candidate for future investigation.

Allopregnanolone involvement in feeding regulation, overeating and obesity

Obesity is strongly associated with ill health, primarily caused by consumption of excessive calories, and promoted (inter alia) by gamma-amino-butyric-acid (GABA) stimulating food intake by activating GABA_A receptors (primarily with α3 and α2 subunits) in the hypothalamic arcuate nucleus and paraventricular nucleus. Allopregnanolone is a potent positive GABA_A receptor modulating steroid (GAMS). As reviewed here, elevated allopregnanolone levels are associated with increases in food intake, preferences for energy-rich food, and obesity in humans and other mammals. In women with polycystic ovarian disease, high serum allopregnanolone concentrations are linked to uncontrolled eating, and perturbed sensitivity to allopregnanolone. Increases in weight during pregnancy also correlate with increases in allopregnanolone levels. Moreover, Prader-Willis syndrome is associated with massive overeating, absence of a GABA_A receptor (with compensatory >12-, >5- and >1.5-fold increases in α4, γ2, and α1, α3 subunits), and increases in the α4, βx, δ receptor subtype, which is highly sensitive to allopregnanolone. GABA and positive GABA-A receptor modulating steroids like allopregnanolone stimulates food intake and weight gain.

Defective insulin signaling and the protective effects of dimethyldiguanide during follicular development in the ovaries of polycystic ovary syndrome

It is established that the physiological effects of insulin are primarily mediated by the insulin signaling pathway. However, a defective insulin signaling is closely associated with the clinical manifestations of polycystic ovary syndrome (PCOS), which include excess androgen levels, insulin resistance and anovulation, and is involved in the pathophysiology of PCOS at the molecular level. Dimethyldiguanide (DMBG) has been widely employed to alleviate reproduction dysfunction in women with PCOS, however, the exact mechanism of this effect remains unclear. The objective of the present study was to investigate the effects of DMBG on the expression of the insulin signaling pathway in the ovaries of rats with PCOS, and to identify the potential underlying molecular mechanisms of these effects in PCOS. In the present study, a PCOS rat model was induced by letrozole, and successful establishment of the model was confirmed by examining ovarian histology and determining serum testosterone levels, by hematoxylin and eosin staining and ELISA, respectively. Subsequently, the expression of two key elements of insulin signaling, insulin receptor substrate (IRS)‑2 and phosphatidylinositol 3‑kinase (PI3K), was determined by immunohistochemistry and western blot analysis. The results demonstrated that IRS‑2 and PI3K expression was markedly decreased in PCOS ovaries, which was rescued by DMBG treatment. These results indicate that IRS‑2/PI3K signaling may be involved in the development of PCOS and the therapeutic effects of DMBG on PCOS. To further confirm the effects of DMBG on insulin signaling expression during this process, the expression of an additional two downstream proteins, phosphoinositide‑dependent kinase‑1 (PDK‑1) and the mammalian target of rapamycin (mTOR), was also investigated in the present study, and the results demonstrated that the expression of PDK‑1 and mTOR was significantly reduced in PCOS ovaries and increased following DMBG treatment, further indicating that altered insulin signaling may have an important role in the development and treatment of PCOS. In conclusion, the results of the present study indicate that the reduced expression of proteins involved in insulin signaling may contribute to the development of the clinical features of PCOS, and DMBG reverses reduced expression of insulin signaling components, by a mechanism that is yet to be determined, to attenuate certain symptoms of PCOS, such as obesity. To the best of our knowledge, the present study is the first to provide data regarding the detailed changes of insulin signaling during the development and treatment of PCOS, and may provide an important reference for clinical PCOS treatment.

Serum vascular endothelial growth factor B is elevated in women with polycystic ovary syndrome and can be decreased with metformin treatment

OBJECTIVE

To determine serum vascular endothelial growth factor B (VEGF-B) levels in polycystic ovary syndrome, their association with insulin resistance and β-cell dysfunction, and the effect of metformin on serum VEGF-B levels.

DESIGN

A cross-sectional, interventional study.

PATIENTS

We recruited 103 women with polycystic ovary syndrome and 96 age-matched healthy controls. Serum VEGF-B levels were determined in all participants, and 44 polycystic ovary syndrome patients randomly received metformin.

MEASUREMENTS

We measured VEGF-B levels in healthy controls and women with polycystic ovary syndrome before and after metformin treatment.

RESULTS

Women with polycystic ovary syndrome had higher serum VEGF-B levels, which decreased with metformin treatment. In the lean and overweight/obese groups, patients with polycystic ovary syndrome had higher plasma VEGF-B levels than did healthy controls (P < 0·05). VEGF-B levels were correlated with body mass index, body fat percentage, M values, homeostasis model assessment of insulin resistance and β-cell function indices. A multiple linear regression analysis showed that VEGF-B level was associated with M values after adjusting for age, body mass index, serum sex hormones and serum lipids in women with polycystic ovary syndrome.

CONCLUSIONS

Serum VEGF-B is significantly higher in women with polycystic ovary syndrome and is closely and positively related to insulin resistance. Metformin treatment reduces VEGF-B levels and ameliorates insulin resistance.

Women with polycystic ovary syndrome have elevated serum concentrations of and altered GABA(A) receptor sensitivity to allopregnanolone

OBJECTIVE

Several studies have reported that γ-aminobutyric acid (GABA) ergic circuits are involved in the pathophysiology of polycystic ovary syndrome (PCOS). The progesterone metabolite allopregnanolone is a potent GABA(A) -receptor-modulating steroid, and patients may have increased concentrations of allopregnanolone or altered GABAA receptor sensitivity. We investigated both of these possibilities in this study.

PATIENTS

We enrolled 9 women with PCOS and 24 age-matched eumenorrhoeic controls, who were divided into two groups by body mass index (BMI) (16 normal weight and 8 overweight).

MEASUREMENTS

We investigated the effects of allopregnanolone injection on GABA(A) receptor sensitivity in both groups of women. All women received a single intravenous dose of allopregnanolone (0·050 mg/kg). GABA(A) receptor sensitivity was assessed with the saccadic eye velocity (SEV) over 30° (SEV30°), the SEV30°/allopregnanolone concentration ([Allo]) ratio, and sedation, which were measured together with serum allopregnanolone at intervals for 180 min after injection. The controls were tested in the follicular phase of the menstrual cycle.

RESULTS

Baseline allopregnanolone concentrations were higher in the PCOS women than in the normal-weight (P = 0·034) and overweight controls (P = 0·004). The allopregnanolone concentrations after injection were higher in the PCOS women (P = 0·006) and overweight controls (P = 0·037) than in the normal-weight controls. All groups showed a decline in the SEV30°/[Allo] ratio after injection. Allopregnanolone had a smaller effect on the SEV30°/[Allo] ratio in the overweight women (PCOS, P = 0·032; controls, P = 0·007) than in the normal-weight controls. The sedation score after allopregnanolone injection was lower in the PCOS patients than in the controls, but was not different between the two control groups.

CONCLUSIONS

PCOS women had elevated baseline allopregnanolone concentrations compared with follicular-phase controls. All overweight women (PCOS and controls) were less sensitive to allopregnanolone than normal-weight controls.

Effects of Roux-en-Y gastric bypass surgery on eating behaviour and allopregnanolone levels in obese women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is associated with abnormal eating habits. We examined whether surgical treatment affected allopregnanolone levels and eating behaviour in nine women with PCOS who qualified for Rou-en-Y gastric bypass surgery. Blood samples were obtained to measure sex-hormone-binding globulin, total testosterone, progesterone, and allopregnanolone, and eating behaviour was evaluated using the Three-Factor Eating Questionnaire before surgery and at 6 and 12 months after surgery. Body mass index and total testosterone levels decreased, and progesterone and sex-hormone-binding globulin levels increased after bariatric surgery compared with pre-surgical values. In patients with anovulatory menstrual cycles, both the serum allopregnanolone level and the allopregnanolone/progesterone ratio were unchanged after surgery. The patients had high uncontrolled and emotional eating scores, and low cognitive restraint scores before surgery, and these scores had improved significantly at 6 and 12 months after surgery. The presurgical allopregnanolone levels were significantly correlated with uncontrolled eating. In conclusion, these results suggest that allopregnanolone appear to be part of the mechanism underlying the abnormal eating behaviour of obese PCOS patients by causing the loss of control over food intake. Roux-en-Y gastric bypass surgery can improve eating behaviour and clinical symptoms, and may facilitate weight loss in obese women with PCOS.

Reproductive neuroendocrine dysfunction in polycystic ovary syndrome: insight from animal models

Polycystic ovary syndrome (PCOS) is a common endocrinopathy with elusive origins. A clinically heterogeneous disorder, PCOS is likely to have multiple etiologies comprised of both genetic and environmental factors. Reproductive neuroendocrine dysfunction involving increased frequency and amplitude of gonadotropin-releasing hormone (GnRH) release, as reflected by pulsatile luteinizing hormone (LH) secretion, is an important pathophysiologic component in PCOS. Whether this defect is primary or secondary to other changes in PCOS is unclear, but it contributes significantly to ongoing reproductive dysfunction. This review highlights recent work in animal models, with a particular emphasis on the mouse, demonstrating the ability of pre- and postnatal steroidal and metabolic factors to drive changes in GnRH/LH pulsatility and GnRH neuron function consistent with the observed abnormalities in PCOS. This work has begun to elucidate how a complex interplay of ovarian, metabolic, and neuroendocrine factors culminates in this syndrome.

Adrenocortical production is associated with higher levels of luteinizing hormone in nonobese women with polycystic ovary syndrome

Objective. Insulin resistance (IR) and ovarian and adrenal hyperandrogenism are a common finding in women with polycystic ovary syndrome (PCOS). The aim of the present study was to access possible differences in insulin resistance, gonadotropins, and androgens production in obese and nonobese PCOS women. Study Design. We studied 37 PCOS women (16 nonobese and 21 obese) and 18 nonobese controls. Fasting glucose, insulin, androgens, and gonadotropins levels were determined. Salivary cortisol was measured basal and in the morning after dexamethasone (DEX) 0.25 mg. Results. Nonobese PCOS women showed higher basal salivary cortisol and serum dehydroepiandrosterone sulfate and luteinizing hormone (LH) levels than controls and obese PCOS. These hormones levels did not differ between the obese and control groups. After DEX administration no differences were found between the three groups. In PCOS women, salivary cortisol levels showed negative correlation with BMI (r = -0.52; P = 0.001) and insulin (r = -0.47; P = 0.003) and positive correlation with LH (r = 0.40; P = 0.016). Conclusion. Our results show an increased adrenocortical production in nonobese PCOS women, not related to IR and associated with a normal hypothalamic-pituitary-adrenal suppression. Higher LH levels might be involved in this event.

Polycystic ovary syndrome: effect and mechanisms of acupuncture for ovulation induction

Polycystic ovary syndrome (PCOS), the most common endocrine disorder among women of reproductive age, is characterized by the coexistence of hyperandrogenism, ovulatory dysfunction, and polycystic ovaries (PCO). PCOS also represents the largest part of female oligoovulatory infertility, and the management of ovulatory and menstrual dysfunction, comprises a third of the high costs of PCOS treatment. Current pharmacological and surgical treatments for reproductive symptoms are effective, however, associated with negative side effects, such as cardiovascular complications and multiple pregnancies. For menstrual irregularities and ovulation induction in women with PCOS, acupuncture has indicated beneficial effects. This review will focus on the results from randomized controlled acupuncture trials for regulation of menstrual dysfunction and for inducing ovulation in women with PCOS although there are uncontrolled trials with nonetheless interesting results. Animal experimental studies will be further discussed when they can provide a more mechanistic explanatory view.

Acupuncture for ovulation induction in polycystic ovary syndrome: a randomized controlled trial

Acupuncture has been demonstrated to improve menstrual frequency and to decrease circulating testosterone in women with polycystic ovary syndrome (PCOS). Our aim was to investigate whether acupuncture affects ovulation frequency and to understand the underlying mechanisms of any such effect by analyzing LH and sex steroid secretion in women with PCOS. This prospective, randomized, controlled clinical trial was conducted between June 2009 and September 2010. Thirty-two women with PCOS were randomized to receive either acupuncture with manual and low-frequency electrical stimulation or to meetings with a physical therapist twice a week for 10-13 wk. Main outcome measures were changes in LH secretion patterns from baseline to after 10-13 wk of treatment and ovulation frequency during the treatment period. Secondary outcomes were changes in the secretion of sex steroids, anti-Müllerian hormone, inhibin B, and serum cortisol. Ovulation frequency during treatment was higher in the acupuncture group than in the control group. After 10-13 wk of intervention, circulating levels of estrone, estrone sulfate, estradiol, dehydroepiandrosterone, dehydroepiandrosterone sulfate, androstenedione, testosterone, free testosterone, dihydrotestosterone, androsterone glucuronide, androstane-3α,17β-diol-3-glucuronide, and androstane-3α,17β-diol-17-glucuronide decreased within the acupuncture group and were significantly lower than in the control group for all of these except androstenedione. We conclude that repeated acupuncture treatments resulted in higher ovulation frequency in lean/overweight women with PCOS and were more effective than just meeting with the therapist. Ovarian and adrenal sex steroid serum levels were reduced with no effect on LH secretion.

Developmental programming: prenatal and postnatal contribution of androgens and insulin in the reprogramming of estradiol positive feedback disruptions in prenatal testosterone-treated sheep

Prenatal testosterone (T) excess compromises the estradiol (E(2)) positive feedback. This study tested the hypothesis that antagonizing androgen action or improving insulin sensitivity prenatally would prevent positive feedback disruptions from developing, whereas postnatal intervention with androgen antagonist or insulin sensitizer would ameliorate the severity of disruptions in prenatal T-treated females. The E(2) positive feedback response was tested at 16 wk of age in the following groups of animals: 1) control, 2) prenatal T, 3) prenatal T plus the androgen antagonist, flutamide, 4) prenatal T plus insulin sensitizer, rosiglitazone, 5) prenatal T and postnatal androgen antagonist, and 6) prenatal T and postnatal insulin sensitizer (n = 7-21 animals/group). Prenatal T treatment involved the administration of T propionate (100 mg, im) twice weekly from d 30 to 90 of gestation. Prenatal interventions involved daily sc administration of androgen antagonist (15 mg/kg) or oral administration of insulin sensitizer (8 mg) for the same duration. Postnatal treatments began at 8 wk of age and involved daily oral administration of androgen antagonist (15 mg/kg) or insulin sensitizer (0.11 mg/kg). None of the prenatal/postnatal interventions increased number of animals responding or prevented the time delay in LH surge response to the E(2) positive feedback challenge. In contrast, the postnatal treatment with androgen antagonist or insulin sensitizer increased total LH released in response to E(2) positive feedback challenge, compared with the T animals. Overall, these interventional studies indicate that timing and magnitude of the LH surge are programmed by different neuroendocrine mechanisms with postnatal androgens and insulin determining the size and prenatal estrogen likely the timing of the LH surge.

Long-term metformin treatment is able to reduce the prevalence of metabolic syndrome and its hepatic involvement in young hyperinsulinaemic overweight patients with polycystic ovarian syndrome

OBJECTIVE

The objective of this study is to determine the ability of metformin treatment in reducing the prevalence of metabolic syndrome (MS) and its hepatic involvement in young hyperinsulinaemic overweight patients with polycystic ovarian syndrome (PCOS).

DESIGN

Clinical Trial.

PATIENTS

We recruited 140 hyperinsulinaemic overweight women with PCOS in their reproductive age. Metformin treatment (500 mg × 3/die) was prescribed to each patient for twelve months.

MEASUREMENTS

The primary outcome was to evaluate the prevalence of nonalcoholic fatty liver disease (NAFLD) and MS in hyperinsulinaemic overweight patients with PCOS. The secondary outcome was to evaluate, in the same patients, the effects of metformin therapy on endocrine, metabolic and hepatic parameters.

RESULTS

At basal evaluation, NAFLD was diagnosed in 81 of 140 patients with PCOS (57·85%); MS was present only in the NAFLD group (32·09%vs 0%; P < 0·001). After twelve months, metformin is able to significantly reduce, in the same group, the prevalence of MS (28·9%vs 13·5%; P < 0·01). An improvement of hepatic parameters and a significant decrease in oligomenorrhea (85·7%vs 19%, P < 0·001) were also observed.

CONCLUSIONS

Treatment with metformin is indicated in all hyperinsulinaemic overweight patients with PCOS, especially in those with NAFLD. These data appear even more interesting considering their increased risk to develop metabolic and hepatic complications.

Use of metformin in the treatment of polycystic ovary syndrome

Metformin is quite an old drug, but it is optimal for the control of glycemia in Type 2 diabetes. It was reported, 15 years ago, that insulin resistance was abnormally high in most polycystic ovary syndrome (PCOS) patients. Starting from that moment, increasing numbers of studies were performed to demonstrate the efficacy of metformin in controlling and/or modulating several aspects of PCOS, which is the most common cause of menstrual irregularity, inesthetisms and infertility. Metformin induces higher glucose uptake, thus inducing a lower synthesis/secretion of insulin. Such an effect permits the possible restoration of the normal biological functions that are severely affected by the compensatory hyperinsulinemia reactive to the increased peripheral insulin resistance. These are the basis of the many positive effects of this drug, such as the restoration of menstrual cyclicity, ovulatory cycles and fertility, because abnormal insulin levels affect the hypothalamus-pituitary-ovarian function, as well as the use of glucose in peripheral tissues. Metformin improves the impairments typically observed in hyperinsulinemic PCOS patients, reducing the possible evolution towards metabolic syndrome and Type 2 diabetes; and when pregnancy occurs, it consistently reduces the risk of gestational diabetes, eclampsia and hypertension. PCOS seems to be the perfect physiopathological condition that might have higher benefits from metformin administration, obviously after Type 2 diabetes. This review focuses on the many aspects of PCOS and on the possible issues of this disease for which metformin might be a putative optimal treatment.

Metformin administration restores allopregnanolone response to adrenocorticotropic hormone (ACTH) stimulation in overweight hyperinsulinemic patients with PCOS

OBJECTIVE

To investigate the adrenal response in terms of allopregnanolone secretion in a group of hyperinsulinemic patients with polycystic ovary syndrome (PCOS).

DESIGN

Controlled clinical study.

SETTING

Patients with PCOS in a clinical research environment.

PATIENTS

Twenty-two overweight patients with PCOS with hyperinsulinism were enrolled after informed consent.

INTERVENTIONS

All patients underwent hormonal evaluations, oral glucose tolerance test (OGTT) and adrenocorticotropic hormone (ACTH) test before and after 4 months of metformin administration (500 mg p.o. bi-daily). Ultrasound examinations and Ferriman-Gallway score were also performed. Main outcome measures. plasma luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin (PRL), estradiol, 17-hydroxy-progesterone (17OHP), androstenedione (A), testosterone (T), allopregnanolone, glucose, insulin, C peptide concentrations, body mass index (BMI).

RESULTS

Metformin administration reduced significantly LH, A, T, insulin and BMI, while allopregnanolone was significantly increased with no change in progesterone plasma levels. Insulin response to OGTT decreased and allopregnanolone response to ACTH stimulation before while this was restored after the treatment interval. The Ferriman-Gallway score as well as the ovarian volume was significantly decreased after 4 months of metformin therapy.

CONCLUSIONS

In overweight patients with PCOS with hyperinsulinism, allopregnanolone secretion is impaired and metformin administration restored normal allopregnanolone concentrations modulating both steroid syntheses from the ovaries and from adrenal gland.

Metformin administration was associated with a modification of LH, prolactin and insulin secretion dynamics in women with polycystic ovarian syndrome

AIM. To elucidate the dynamics of FSH, LH, prolactin (PRL), TSH and insulin secretion in women with polycystic ovarian syndrome (PCOS) treated with metformin (MET).

PATIENTS AND METHODS

In a prospective, controlled and randomised trial, 32 women with PCOS and 32 with normal cycle were recruited to receive MET (850 mg b.i.d.) or placebo (n: 16 for each subgroup) for an average of 40 days. Pituitary function and insulin secretion were assessed before and after intervention by GnRH-TRH tests and oral glucose tolerance test induced insulin response.

RESULTS

Basal and area under the response curve (AURC) LH values were higher in PCOS than in normal controls before MET and declined following treatment in the former group (P < 0.05). Ovulatory PCOS responders had lower basal LH, AURC(LH) and AURC(PRL) values during MET than anovulatory cases (P < 0.05 for all) and AURCins was lower in ovulatory than anovulatory PCOS before and on MET (P < 0.02-P < 0.05), with a rise of QUICKY index in the former group during MET treatment (P < 0.05). FSH and TSH were similar.

CONCLUSIONS

MET administration lowered LH activity in all PCOS women and in ovulatory responders and also compromised PRL stimulated secretion in the latter cases. These findings were indicative of an effect of MET on pituitary activity.

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.

Abnormal response of insulin to glucose loading and assessment of insulin resistance in non-obese patients with polycystic ovary syndrome

OBJECTIVES

To investigate the insulin response to glucose loading and to determine which method is best in order to evaluate insulin resistance in women with polycystic ovary syndrome (PCOS).

METHODS

In order to eliminate the influence of obesity on the variables, all subjects were non-obese. Standard oral glucose tolerance tests were performed in 23 normal women and 21 patients with PCOS. Insulin resistance was evaluated by the homeostasis model assessment insulin resistance index (HOMA-IR), homeostasis model assessment for beta-cell function (HOMA-%B), the quantitative insulin-sensitivity check index (QUICKI) and area under the curve for glucose (AUC(glucose)) and insulin (AUC(insulin)).

RESULTS

The mean values of HOMA-IR, AUC(insulin) and AUC(glucose) in the PCOS group were significantly higher than in the BMI-matched normal control group (p < 0.05, p < 0.01 and p < 0.01, respectively). There were significant positive correlations between AUC(insulin) and AUC(glucose) and androgens or luteinizing hormone in all subjects (p < 0.001). However, HOMA-IR and fasting insulin were significantly correlated only with total testosterone (p < 0.05). AUC(insulin) and AUC(glucose) values were elevated in more than 50% of PCOS patients with normal values of HOMA indices.

CONCLUSION

In the PCOS group, the abnormal response of insulin to glucose loading was suggested. AUC(insulin) may be a better index than others to evaluate insulin resistance in non-obese PCOS patients.