Metformin treatment reduces ovarian cytochrome P-450c17alpha response to human chorionic gonadotrophin in women with insulin resistance-related polycystic ovary syndrome

Multicenter Analysis of Cardiometabolic-Related Diagnoses in Youth with Congenital Adrenal Hyperplasia: a PEDSnet study

CONTEXT

Small cohorts of youth with congenital adrenal hyperplasia (CAH) demonstrate increased risk of obesity and poor cardiometabolic health.

OBJECTIVE

To determine the odds of cardiometabolic-related diagnoses in youth with CAH compared to matched controls in a cross-sectional analysis in a large, multisite database (PEDSnet).

DESIGN

Electronic health record data (2009-2019) were used to determine odds of cardiometabolic-related outcomes based on diagnosis, anthropometric and laboratory data using logistic regression among youth with CAH vs. controls.

SETTING

Six PEDSnet sites.

PATIENTS OR OTHER PARTICIPANTS

Youth with CAH and >1 outpatient visit in PEDSnet (n=1,647) were propensity-score matched on 8 variables to controls (n=6,588). A subset of youth with classic CAH (n=547, with glucocorticoid and mineralocorticoid prescriptions) were matched to controls (n=2,188).

INTERVENTION(S)

N/A.

MAIN OUTCOME MEASURE(S)

Odds of having cardiometabolic-related diagnoses among youth over 2 years with CAH compared to matched controls.

RESULTS

Outcomes were calculated for all individuals with CAH (median age at last visit 12.9 years [7.3, 17.6]) and a subset with classic CAH (median age at last visit 11.6 years [4.7, 17.5]) compared to their matched controls. All patients with CAH had higher odds of overweight/obesity (odds ratio [95% confidence interval] 3.63 [3.24,4.07]), hypertension (3.07 [2.60,3.64]), dysglycemia (1.95 [1.35,2.82], dyslipidemia (2.28 [1.79,2.91]) and liver dysfunction (2.30 [1.91,2.76]) compared to matched controls. Patients with classic CAH had higher odds of overweight/obesity (3.21 [2.61,3.93]), hypertension (8.22 [6.71,10.08]), and liver dysfunction (2.11 [1.55,2.89]) compared to matched controls.

CONCLUSIONS

Overall, youth with CAH are at increased risk of diagnoses related to worse cardiometabolic health.

A novel action of insulin sensitizing drug as a potential promotor of preovulatory follicles, ovulation rate and prolificacy in sheep

The effect of the insulin-sensitizing drug metformin on preovulatory follicle (POF) number, ovulation rate, fetal rate and prolificacy was studied in forty-six cyclic Malpura ewes. After estrus synchronization, the ewes were equally divided into two groups (n = 23). The treatment group (MET) received a daily oral dose of metformin at a rate of 500 mg/animal for approximately 12 weeks, spanning five estrous cycles, as against untreated control (CON). All the ewes were bred to proven rams at the end of treatment. Ovarian ultrasound scans were performed at each estrus and day 9 of each cycle to assess the number and diameter of POFs and corpora lutea (CL), respectively. A comprehensive assessment of circulating hormones including, estradiol, progesterone, androstenedione, and insulin as well as metabolic indicators such as glucose, and lipid profile parameters was performed. At the end of treatment on the day of estrus (E5D0), the treatment showed a stimulatory effect on follicular development with a 53.2% (P < 0.001) increase in the number of POFs. It also increased the ovulation rate by 67.4% (P < 0.01), with a higher proportion (χ2df1 = 10.7, P < 0.001) of ewes in the MET group having multiple ovulations compared to the CON group (82.6 vs. 30.4%). With 1.48 ± 0.12 prolificacy rate in MET ewes, the proportion of ewes giving birth to multiple lambs was 2.9-fold higher than in the CON group. Plasma estradiol, insulin, glucose, total cholesterol, and LDL-cholesterol concentrations were lower (P < 0.05) in the MET ewes than in the CON. The results of the present study indicate that metformin can increase the number of POF, ovulation rate, fetal rate and prolificacy in ewes, while reducing the plasma estradiol, insulin, glucose and cholesterol in MET ewes.

Promising drug candidates for the treatment of polycystic ovary syndrome (PCOS) as alternatives to the classical medication metformin

Polycystic ovary syndrome (PCOS) is a prevalent hormonal disorder that affects women of reproductive age. It is characterized by abnormal production of androgens, typically present in small quantities in females. This study aimed to investigate the therapeutic potential of Irosustat (STX64), STX140, and compound 1G as new drug candidates for the treatment of letrozole-induced PCOS in female Wistar rats. 36 rats were divided into six groups of equal size. PCOS was induced in all groups, except the normal control group, by administering letrozole orally (1 mg/kg/day for 35 days). The onset of abnormal estrous cycle was confirmed by examining daily vaginal smears under a microscope. Subsequently, each rat group was assigned to a different treatment regimen, including one control group, one letrozole group, one metformin group (500 mg/kg/day) as a reference drug, and the other groups received a different drug candidate orally for 30 days. After treatment, blood collection was performed for biochemical measurements and determination of oxidative stress markers. The rats were dissected to separate ovaries and uterus for morphological, histological, and western blotting studies. Treatment with the drug candidates improved the ovaries and uterus weight measurements compared to the untreated PCOS group. The three tested drug candidates demonstrated promising improvements in lipid profile, blood glucose level, testosterone, progesterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol levels. In addition, western blotting confirmed their promising effects on Akt, mTOR, and AMPK-α pathways. This study led to the discovery of three promising drug candidates for the management of PCOS as alternatives to metformin.

Management aspects of congenital adrenal hyperplasia during adolescence and transition to adult care

The adolescent period is characterised by fundamental hormonal changes, which affect sex steroid production, cortisol metabolism and insulin sensitivity. These physiological changes have a significant impact on patients with congenital adrenal hyperplasia (CAH). An essential treatment aim across the lifespan in patients with CAH is to replace glucocorticoids sufficiently to avoid excess adrenal androgen production but equally to avoid cardiometabolic risks associated with excess glucocorticoid intake. The changes to the hormonal milieu at puberty, combined with poor adherence to medical therapy, often result in unsatisfactory control exacerbating androgen excess and increasing the risk of metabolic complications due to steroid over-replacement. With the physical and cognitive maturation of the adolescent with CAH, fertility issues and sexual function become a new focus of patient care in the paediatric clinic. This requires close surveillance for gonadal dysfunction, such as irregular periods/hirsutism or genital surgery-associated symptoms in girls and central hypogonadism or testicular adrenal rest tumours in boys. To ensure good health outcomes across the lifespan, the transition process from paediatric to adult care of patients with CAH must be planned carefully and early from the beginning of adolescence, spanning over many years into young adulthood. Its key aims are to empower the young person through education with full disclosure of their medical history, to ensure appropriate follow-up with experienced physicians and facilitate access to multispecialist teams addressing the complex needs of patients with CAH.

Comprehensive Analysis of Gut Microbiota Alteration in the Patients and Animal Models with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common disease of endocrine-metabolic disorder, and its etiology remains largely unknown. The gut microbiota is possibly involved in PCOS, while the association remains unclear. The comprehensive analysis combining gut microbiota with PCOS typical symptoms was performed to analyze the role of gut microbiota in PCOS in this study. The clinical patients and letrozole-induced animal models were determined on PCOS indexes and gut microbiota, and fecal microbiota transplantation (FMT) was conducted. Results indicated that the animal models displayed typical PCOS symptoms, including disordered estrous cycles, elevated testosterone levels, and ovarian morphological change; meanwhile, the symptoms were improved after FMT. Furthermore, the microbial diversity exhibited disordered, and the abundance of the genus Ruminococcus and Lactobacillus showed a consistent trend in PCOS rats and patients. The microbiota diversity and several key genera were restored subjected to FMT, and correlation analysis also supported relevant conclusions. Moreover, LEfSe analysis showed that Gemmiger, Flexispira, and Eubacterium were overrepresented in PCOS groups. Overall, the results indicate the involvement of gut microbiota in PCOS and its possible alleviation of endocrinal and reproductive dysfunctions through several special bacteria taxa, which can function as the biomarker or potential target for diagnosis and treatment. These results can provide the new insights for treatment and prevention strategies of PCOS.

Key signalling pathways underlying the aetiology of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine condition characterised by a range of reproductive, endocrine, metabolic and psychological abnormalities. Reports estimate that around 10% of women of reproductive age are affected by PCOS, representing a significant prevalence worldwide, which poses a high economic health burden. As the origin of PCOS remains largely unknown, there is neither a cure nor mechanism-based treatments leaving patient management suboptimal and focused solely on symptomatic treatment. However, if the underlying mechanisms underpinning the development of PCOS were uncovered then this would pave the way for the development of new interventions for PCOS. Recently, there have been significant advances in our understanding of the underlying pathways likely involved in PCOS pathogenesis. Key insights include the potential involvement of androgens, insulin, anti-Müllerian hormone and transforming growth factor beta in the development of PCOS. This review will summarise the significant scientific discoveries on these factors that have enhanced our knowledge of the mechanisms involved in the development of PCOS and discuss the impact these insights may have in shaping the future development of effective strategies for women with PCOS.

Role of insulin and insulin resistance in androgen excess disorders

Insulin has complex effects on cell growth, metabolism and differentiation, and these effects are mediated by a cell-surface bound receptor and eventually a cascade of intracellular signaling events. Among the several metabolic and growth-promoting effects of insulin, insulin resistance is defined as an attenuated effect of insulin on glucose metabolism, primarily the limited export of blood glucose into skeletal muscle and adipose tissue. On the other hand, not all the signaling pathways and insulin-responsive tissues are equally affected, and some effects other than the metabolic actions of insulin are overexpressed. Ovaries and the adrenal glands are two examples of tissues remaining sensitive to insulin actions where insulin may contribute to increased androgen secretion. Polycystic ovary syndrome (PCOS) is the most common form of androgen excess disorder (AED), and its pathogenesis is closely associated with insulin resistance. Patients with idiopathic hirsutism also exhibit insulin resistance, albeit lower than patients with PCOS. Although it is not as evident as in PCOS, patients with congenital adrenal hyperplasia may have insulin resistance, which may be further exacerbated with glucocorticoid overtreatment and obesity. Among patients with severe insulin resistance syndromes, irrespective of the type of disease, hyperinsulinemia promotes ovarian androgen synthesis independently of gonadotropins. It is highly debated in whom and how insulin resistance should be diagnosed and treated among patients with AEDs, including PCOS. It is not suitable to administer an insulin sensitizer relying on only some mathematical models used for estimating insulin resistance. Instead, the treatment decision should be based on the constellation of the signs, symptoms and presence of obesity; acanthosis nigricans; and some laboratory abnormalities such as impaired glucose tolerance and impaired fasting glucose.

Role of Lipotoxicity and Contribution of the Renin-Angiotensin System in the Development of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common and significant condition associated with hyperandrogenism, infertility, low quality of life, and metabolic comorbidities. One possible explanation of PCOS development is cellular dysfunction induced by nonesterified fatty acids (NEFAs), that is, lipotoxicity, which could explain both the hyperandrogenemia and insulin resistance that characterize women with PCOS. The literature suggests that androgen biosynthesis may be induced by overexposure of androgen-secreting tissues to NEFA and/or defective NEFA metabolism, leading to lipotoxic effects. Indeed, lipotoxicity could trigger androgenic hyperresponsiveness to insulin, LH, and ACTH. In most PCOS women, lipotoxicity also causes insulin resistance, inducing compensatory hyperinsulinemia, and may thus further increase hyperandrogenemia. Many approaches aimed at insulin sensitization also reduce lipotoxicity and have been shown to treat PCOS hyperandrogenemia. Furthermore, our group and others found that angiotensin II type 2 receptor (AT2R) activation is able to improve lipotoxicity. We provided evidence, using C21/M24, that AT2R activation improves adipocytes' size and insulin sensitivity in an insulin-resistant rat model, as well as androgen levels in a PCOS obese rat model. Taken together, these findings point toward the important role of lipotoxicity in PCOS development and of the RAS system as a new target for the treatment of PCOS.

Follicular hyperandrogenism and insulin resistance in polycystic ovary syndrome patients with normal circulating testosterone levels

Polycystic ovary syndrome (PCOS) is a common reproductive disease with high heterogeneity. The role of excess androgen in PCOS etiology remains disputed, since around 20%-50% of PCOS women do not display hyperandrogenemia. The microenvironment of the ovary critically influences follicular development. In the present study, we assessed the role of androgen in PCOS by investigating whether excessive follicular fluid androgen was present in PCOS patients with normal serum androgen levels and influenced by follicular fluid insulin resistance (IR). Follicular fluid samples of 105 women with PCOS and 105 controls were collected. Levels of steroid hormones, glucose and insulin in the follicular fluid were examined and compared with data from serum biochemistry tests. We found that 64.9% (63/97) of PCOS patients with normal serum androgen levels displayed abnormally high follicular fluid androgen level. The follicular fluid androgen level was positively correlated with follicular fluid IR within a certain range and follicular fluid estrogen-to-testosterone (E2/T) ratio was significantly reduced in these patients. These results indicated that there existed a subgroup of PCOS patients who displayed excessive follicular fluid androgen and IR despite their normal circulating testosterone (T) levels. Our study highlights the importance of ovary hyperandrogenism and IR in the etiology of PCOS.

Genetic, hormonal and metabolic aspects of PCOS: an update

Polycystic ovary syndrome (PCOS) is a complex endocrine disorder affecting 5-10 % of women of reproductive age. It generally manifests with oligo/anovulatory cycles, hirsutism and polycystic ovaries, together with a considerable prevalence of insulin resistance. Although the aetiology of the syndrome is not completely understood yet, PCOS is considered a multifactorial disorder with various genetic, endocrine and environmental abnormalities. Moreover, PCOS patients have a higher risk of metabolic and cardiovascular diseases and their related morbidity, if compared to the general population.

The Deep Correlation between Energy Metabolism and Reproduction: A View on the Effects of Nutrition for Women Fertility

In female mammals, mechanisms have been developed, throughout evolution, to integrate environmental, nutritional and hormonal cues in order to guarantee reproduction in favorable energetic conditions and to inhibit it in case of food scarcity. This metabolic strategy could be an advantage in nutritionally poor environments, but nowadays is affecting women's health. The unlimited availability of nutrients, in association with reduced energy expenditure, leads to alterations in many metabolic pathways and to impairments in the finely tuned inter-relation between energy metabolism and reproduction, thereby affecting female fertility. Many energetic states could influence female reproductive health being under- and over-weight, obesity and strenuous physical activity are all conditions that alter the profiles of specific hormones, such as insulin and adipokines, thus impairing women fertility. Furthermore, specific classes of nutrients might affect female fertility by acting on particular signaling pathways. Dietary fatty acids, carbohydrates, proteins and food-associated components (such as endocrine disruptors) have per se physiological activities and their unbalanced intake, both in quantitative and qualitative terms, might impair metabolic homeostasis and fertility in premenopausal women. Even though we are far from identifying a "fertility diet", lifestyle and dietary interventions might represent a promising and invaluable strategy to manage infertility in premenopausal women.

Leuprolide acetate-stimulated androgen response during female puberty

BACKGROUND

A physiological increase in androgen levels occurs during adolescence. Measuring androgen concentrations is the best method to distinguish normal evolution processes from hyperandrogenic disorders.

HYPOTHESIS

The increase in circulating androgens during puberty is inversely associated with insulin sensitivity in normal weight girls.

OBJECTIVE

To assess circulating levels of ovarian androgens and anti-Müllerian hormone (AMH) at baseline and after GnRH analogue (GnRH-a) stimulation in normal pubertal girls across different Tanner stages. We also studied the association between this response and insulin sensitivity.

DESIGN

Prospective study of healthy girls (6-12 years) from the local community (n = 63).

METHODS

Tanner I (n = 23) subjects were assessed cross-sectionally, and Tanner II girls (n = 40) were evaluated every 6 months until they reached Tanner V. Early morning dehydroepiandrosterone sulphate (DHEA-S), AMH, sex hormone-binding globulin (SHBG), androstenedione, glucose and insulin levels were measured. A GnRH-a test (500 μg/m(2) ; sc) and oral glucose intolerance test (OGTT) were performed. Differences throughout puberty were evaluated.

RESULTS

Basal and/or stimulated Testosterone DHEA-S and 17-hydroxyprogesterone (17OHP) were inversely associated with insulin sensitivity (WIBSI) from the beginning of puberty, whereas androstenedione was directly associated with gonadotrophins. AMH was inversely associated with basal and stimulated gonadotrophins and directly with insulin area under the curve (AUC) only in the early stages of puberty. 17OHP and testosterone responsiveness increased significantly during puberty in all subjects, whereas testosterone levels changed less consistently. This pattern of ovarian-steroidogenic response was most evident during mid- and late puberty. Moreover, during late puberty only, basal 17OHP, testosterone and DHEA-S were positively associated with gonadotrophins.

CONCLUSION

In normal nonobese girls born appropriate for gestational age, androgen synthesis was associated with insulin sensitivity in early puberty and with LH only in late puberty.

AMPK: a master energy regulator for gonadal function

From C. elegans to mammals (including humans), nutrition and energy metabolism significantly influence reproduction. At the cellular level, some detectors of energy status indicate whether energy reserves are abundant (obesity), or poor (diet restriction). One of these detectors is AMPK (5′ AMP-activated protein kinase), a protein kinase activated by ATP deficiency but also by several natural substances such as polyphenols or synthetic molecules like metformin, used in the treatment of insulin resistance. AMPK is expressed in muscle and liver, but also in the ovary and testis. This review focuses on the main effects of AMPK identified in gonadal cells. We describe the role of AMPK in gonadal steroidogenesis, in proliferation and survival of somatic gonadal cells and in the maturation of oocytes or spermatozoa. We discuss also the role of AMPK in germ and somatic cell interactions within the cumulus-oocyte complex and in the blood testis barrier. Finally, the interface in the gonad between AMPK and modification of metabolism is reported and discussion about the role of AMPK on fertility, in regards to the treatment of infertility associated with insulin resistance (male obesity, polycystic ovary syndrome).

The correlation of aromatase activity and obesity in women with or without polycystic ovary syndrome

Background

This study aimed to investigate the effect of polycystic ovary syndrome (PCOS) on the association of aromatase activity assessed by estradiol-to-testosterone ratio (E₂/T) with body mass index (BMI) in women.

Methods

This was a cohort study in five centers for reproductive medicine in China. Data were collected from July 2012 to December 2013. PCOS patients (n = 785) and non PCOS, healthy, age-matched controls (n = 297) were included. Plasma sex hormones including estradiol (E₂), testosterone (T), follicle stimulating hormone (FSH), and luteinizing hormone (LH) were measured by ELISA, together with BMI and E₂/T being calculated, on the third day of the menstrual cycle. Aromatase activity in PCOS patients with different BMI, T and E₂ levels were compared.

Results

E₂/T was significantly lower (P < 0.05) while BMI was significantly increased (P < 0.05) in PCOS than non-PCOS. No significant difference was observed in E₂/T among different BMI subgroups of either PCOS or control. Ovarian aromatase activity was decreased in PCOS patients which was independent of BMI. Hyperestrogen promoted ovarian aromatase activity, while hyperandrogen inhibited such activity, both in a dose-dependent, biphasic manner.

Conclusions

Ovarian aromatase activity was lower in PCOS, which was independent of BMI. New therapeutic strategies can be developed by targeting aromatase activity for treating PCOS women, especially those with obesity.

Metformin improves glucose effectiveness, not insulin sensitivity: predicting treatment response in women with polycystic ovary syndrome in an open-label, interventional study

CONTEXT

Although metformin is widely used to improve insulin resistance in women with polycystic ovary syndrome (PCOS), its mechanism of action is complex, with inconsistent effects on insulin sensitivity and variability in treatment response.

OBJECTIVE

The aim of the study was to delineate the effect of metformin on glucose and insulin parameters, determine additional treatment outcomes, and predict patients with PCOS who will respond to treatment.

DESIGN AND SETTING

We conducted an open-label, interventional study at an academic medical center.

SUBJECTS

Women with PCOS (n = 36) diagnosed by the National Institutes of Health criteria participated in the study.

INTERVENTIONS

Subjects underwent fasting blood sampling, an IV glucose tolerance test, dual-energy x-ray absorptiometry scan, transvaginal ultrasound, and measurement of human chorionic gonadotropin-stimulated androgen levels before and after 12 weeks of treatment with metformin extended release 1500 mg/d. Interval visits were performed to monitor anthropometric measurements and menstrual cycle parameters.

MAIN OUTCOME MEASURES

Changes in glucose and insulin parameters, androgen levels, anthropometric measurements, and ovulatory menstrual cycles were evaluated.

RESULTS

Insulin sensitivity did not change despite weight loss. Glucose effectiveness (P = .002) and the acute insulin response to glucose (P = .002) increased, and basal glucose levels (P = .001) decreased after metformin treatment. T levels also decreased. Women with improved ovulatory function (61%) had lower baseline T levels and lower baseline and stimulated T and androstenedione levels after metformin treatment (all P < .05).

CONCLUSIONS

Using an IV glucose tolerance test, which distinguishes improvements in glucose effectiveness and insulin sensitivity, metformin does not improve insulin sensitivity in women with PCOS but does improve glucose effectiveness. The improvement in glucose effectiveness may be partially mediated by decreased glucose levels. T levels also decreased with metformin treatment. Ovulation during metformin treatment was associated with lower baseline T levels and greater T and androstenedione decreases during treatment, but not with insulin or LH levels. Thus, the action of metformin in PCOS primarily affects glucose levels and steroidogenesis, which may be mediated by mechanisms that affect both pathways, such as inhibition of mitochondrial complex I.

Impact of metformin monotherapy versus metformin with oestrogen-progesterone on lipids in adolescent girls with polycystic ovarian syndrome

OBJECTIVE

Hyperinsulinaemia is an important determinant of the polycystic ovarian syndrome (PCOS). In addition to lifestyle measures, therapeutic strategies include the use of oestrogen-progesterone combination pills (EP), and insulin sensitizers such as metformin, either alone or in combination. Data are limited regarding the impact of metformin alone vs metformin with EP on cardiometabolic risk in overweight adolescents with PCOS. We hypothesized that metformin alone would lead to an improvement in HbA1C and lipid levels in overweight adolescent girls with PCOS compared with meformin with EP.

STUDY DESIGN

Retrospective clinic-based therapy.

PATIENTS AND MEASUREMENTS

We examined the effects of therapy with metformin alone (n = 14) vs metformin with EP (n = 13) on HbA1C and lipid parameters over 10-14 months in 27 overweight girls, drawn from a clinic population of adolescents with PCOS.

RESULTS

The groups did not differ for age, body mass index (BMI), HbA1C or baseline lipids. After at least 10 months, the metformin only group compared with the metformin and EP group had a decrease in total cholesterol (-0·605 ± 0·100 vs 0·170 ± 0·348 mm, P = 0·02, nonparametric test) and triglycerides (-0·342 ± 0·184 vs 0·262 ± 0·133 mm, P = 0·02), despite similar changes in BMI (-1·6 ± 0·7 vs 0·6 ± 2·1 kg/m(2) , P = 0·25) and HbA1C (0·03 ± 0·06 vs 0·03 ± 0·13%, P = 0·99). Differences between groups remained significant after controlling for baseline parameters and for changes in BMI.

CONCLUSION

Metformin alone more effectively improves lipid parameters than metformin with EP in adolescent PCOS, as indicated by a decrease in total cholesterol and triglycerides. This effect is not related to BMI changes.

State of the Art Review: Emerging Therapies: The Use of Insulin Sensitizers in the Treatment of Adolescents with Polycystic Ovary Syndrome (PCOS)

PCOS, a heterogeneous disorder characterized by cystic ovarian morphology, androgen excess, and/or irregular periods, emerges during or shortly after puberty. Peri- and post-pubertal obesity, insulin resistance and consequent hyperinsulinemia are highly prevalent co-morbidities of PCOS and promote an ongoing state of excess androgen. Given the relationship of insulin to androgen excess, reduction of insulin secretion and/or improvement of its action at target tissues offer the possibility of improving the physical stigmata of androgen excess by correction of the reproductive dysfunction and preventing metabolic derangements from becoming entrenched. While lifestyle changes that concentrate on behavioral, dietary and exercise regimens should be considered as first line therapy for weight reduction and normalization of insulin levels in adolescents with PCOS, several therapeutic options are available and in wide use, including oral contraceptives, metformin, thiazolidenediones and spironolactone. Overwhelmingly, the data on the safety and efficacy of these medications derive from the adult PCOS literature. Despite the paucity of randomized control trials to adequately evaluate these modalities in adolescents, their use, particularly that of metformin, has gained popularity in the pediatric endocrine community. In this article, we present an overview of the use of insulin sensitizing medications in PCOS and review both the adult and (where available) adolescent literature, focusing specifically on the use of metformin in both mono- and combination therapy.

Role of the peroxisome proliferator-activated receptors, adenosine monophosphate-activated kinase, and adiponectin in the ovary

The mechanisms controlling the interaction between energy balance and reproduction are the subject of intensive investigations. The integrated control of these systems is probably a multifaceted phenomenon involving an array of signals governing energy homeostasis, metabolism, and fertility. Two fuel sensors, PPARs, a superfamily of nuclear receptors and the kinase AMPK, integrate energy control and lipid and glucose homeostasis. Adiponectin, one of the adipocyte-derived factors mediate its actions through the AMPK or PPARs pathway. These three molecules are expressed in the ovary, raising questions about the biological actions of fuel sensors in fertility and the use of these molecules to treat fertility problems. This review will highlight the expression and putative role of PPARs, AMPK, and adiponectin in the ovary, particularly during folliculogenesis, steroidogenesis, and oocyte maturation.

Thiazolidinediones and Fertility in Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is the most frequent cause of female infertility. The treatment of PCOS patients with insulin sensitizers, such as metformin or thiazolidinediones, increases the ovulation rate and the number of successful pregnancies. The positive action of the insulin-sensitizing treatments could be explained by a decrease in the peripheral insulin resistance but also by a direct action at the ovarian level. We report in this review different hypotheses of thiazolidinediones actions to improve PCOS (steroid secretion by ovarian cells ; insulin sensitivity in muscle and adipocyte and fat redistribution).

Metformin inhibits aromatase via an extracellular signal-regulated kinase-mediated pathway

Metformin treatment, now widely prescribed in polycystic ovary syndrome, is aimed at correcting the associated insulin resistance, but it has also been shown to directly inhibit ovarian steroidogenesis. The mechanisms, however, by which metformin inhibits estradiol production in human granulosa cells remains unknown. Granulosa luteal cells were incubated with metformin, insulin, or combined metformin and insulin treatment, and aromatase mRNA expression was quantified using real-time RT-PCR. Enzyme activity was assessed by the conversion of (3)H-androstenedione to estrone and estradiol. Metformin's effect on the expression of specific untranslated first exon aromatase promoters was analyzed using semiquantitative PCR. The involvement of MAPK kinase (MEK)/ERK pathway was investigated by immunoblotting for aromatase, phosphorylated, and total ERK-1,2 from cells cultured as above with/without the MEK inhibitor PD98059. Metformin significantly inhibited basal and insulin-stimulated aromatase mRNA expression, with parallel results from the aromatase activity assay and protein assessment. This suppression was via down-regulation of aromatase promoter II, I.3, and 1.4 expression and was reversed by the addition of PD98059. Involvement of the ERK signaling pathway was demonstrated by the significant increase in phosphorylated ERK-1,2 with the combined metformin and insulin treatment. We have shown for the first time in human granulosa cells that metformin signficantly attenuated basal and insulin-stimulated P450 aromatase mRNA expression and activity, via silencing of key promoters. This occurred by activation of MEK/ERK pathway, which negatively regulated aromatase production. This is an important consideration given metformin's widespread use in polycystic ovary syndrome and may further support a possible therapeutic indication in estrogen-dependent breast tumors.

In polycystic ovary syndrome, adrenal steroids are regulated differently in the morning versus in response to nutrient intake

OBJECTIVE

To investigate adrenal steroid regulation in polycystic ovary syndrome.

DESIGN

Five-hour oral glucose tolerance test (OGTT) and frequently sampled-intravenous gluclose tolerance test.

SETTING

University research center.

PATIENT(S)

Thirty patients.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Anthropometrics, leptin, cortisol, DHEAS, glucose, insulin.

RESULT(S)

Morning cortisol correlated with sensitivity index (SI, r = .540), DHEAS correlated inversely with age (r = -.6359), body mass index (BMI, r = -.6199), fat mass (r = -0.630), and leptin (r = -0.5676). Between the second and fourth hour of OGTT, cortisol changes (Delta) exhibited three patterns: I, responders (n = 9, Delta: 10.7 +/- 1.0 microg/dL); II, nonresponders (n = 10, Delta: -3.5 +/- 0.6 microg/dL); III, intermediates (n = 11, Delta: 4.3 +/- 1.0 microg/dL). Compared with nonresponders, responders were more obese (BMI: 37.0 +/- 1.6 vs. 31.7 +/- 1.8 kg/m(2)); had higher leptin (28.9 +/- 1.7 vs. 24.1 +/- 1.1 ng/mL), and lower DHEAS (133 +/- 12 vs. 236 +/- 32 ng/mL), higher glucose at 1 h of OGTT (195 +/- 13 vs. 131 +/- 12 mg/dL), higher area under the curve (AUC)(Glucose) (332 +/- 20 vs. 265 +/- 17 mg/dL), higher AUC(Insulin) (244 +/- 50 vs. 125 +/- 30 muU/mL), and lower nadir glucose (61 +/- 2 vs. 70 +/- 2 mg/dL).

CONCLUSION(S)

Obesity and insulin resistance are associated with lower morning cortisol and DHEAS but increased cortisol and DHEA responses after glucose ingestion. Morning steroid levels may not reflect the day-long exposure.

Insulin sensitizers for women with polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) is the most frequent endocrine disorder and most common cause of anovulation in women of reproductive age. It is a heterogeneous disorder, characterized by excess androgen, ovulatory dysfunction and/or polycystic ovaries. The syndrome is known for its association with several reproductive problems, including infertility and obstetric adverse effects. In addition, significant long-term health problems have been strongly linked to PCOS, with women suffering from the disorder having a significantly higher risk of diabetes, cardiovascular risk and some types of cancer, such as endometrial cancer. Although its etiology is unknown, insulin resistance is believed to play a pivotal role in its pathophysiology, with insulin sensitizers found to provide an exciting option in managing health problems associated with PCOS. Almost a decade ago, we proposed a non-insulin-sensitizing mechanism of action for insulin sensitizers through their effect on steroidogenesis. Accumulating evidence supported such an assumption, with solid evidence for a modulating effect on steroidogenesis by metformin and glitazones in the ovaries, adrenal glands and fat cells. Furthermore, other exciting positive roles for insulin sensitizers, in particular glitazones, have been reported at the level of endothelial function. Studying the value of insulin sensitizers in preventing long-term health problems in women with PCOS is still in the stage of infancy.

Metabolic and hormonal changes induced by pioglitazone in polycystic ovary syndrome: a randomized, placebo-controlled clinical trial

CONTEXT

Polycystic ovary syndrome (PCOS) is characterized by insulin resistance, compensatory hyperinsulinemia, increased prevalence of impaired glucose tolerance, and increased ovarian androgen biosynthesis.

OBJECTIVE

The aim of the study was to evaluate effects of pioglitazone on whole body insulin action and ovarian androgen biosynthesis in PCOS.

DESIGN

We performed a randomized placebo-controlled trial.

SETTING

The study was conducted at the Special Diagnostic and Treatment Unit of the Veterans Affairs Medical Center, San Diego, and the University of California, San Diego, General Clinical Research Center.

PATIENTS OR OTHER PARTICIPANTS

A total of 23 subjects with PCOS were evaluated at baseline and end of treatment. Six age- and body mass index-matched women without PCOS were normal controls for baseline evaluation.

INTERVENTION

Subjects with PCOS were randomized to oral placebo or pioglitazone 45 mg daily for 6 months.

MAIN OUTCOME MEASURE(S)

The primary outcome measures were whole body insulin action as measured by hyperinsulinemic euglycemic clamp and ovarian androgen biosynthesis as measured by leuprolide-stimulated production of 17-hydroxyprogesterone (17-OHP).

RESULTS

Compared with placebo, pioglitazone treatment significantly improved multiple measures of insulin action, including glucose disposal rate (P < 0.01), 2-h glucose during 75-g oral glucose tolerance test (P < 0.01), area under the curve glucose during oral glucose tolerance test (P < 0.01), serum adiponectin (P < 0.01), and fasting hyperinsulinemia (P < 0.01). Compared to placebo, pioglitazone treatment reduced the increment of leuprolide-stimulated 17-OHP (P < 0.02). Improvements in glucose disposal rate correlated with reductions in 17-OHP stimulation (P < 0.02).

CONCLUSIONS

Compared to placebo, pioglitazone treatment in PCOS was associated with improvements in insulin action and glucose homeostasis and ameliorated the hyperandrogenic ovarian response.

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.

The serine phosphorylation hypothesis of polycystic ovary syndrome: a unifying mechanism for hyperandrogenemia and insulin resistance

Polycystic ovary syndrome (PCOS) is a common endocrinopathy affecting 4%-8% of reproductive-aged women. The syndrome is characterized by hyperandrogenemia and disordered gonadotropin secretion and is often associated with insulin resistance. However, rather than being one disease entity caused by a single molecular defect, PCOS under its current diagnostic criteria most likely includes a number of distinct disease processes with similar clinical phenotypes but different pathophysiologic mechanisms. The serine phosphorylation hypothesis can potentially explain two major features of PCOS--hyperandrogenemia and insulin resistance. Further defining the molecular mechanisms regulating androgen biosynthesis and insulin action in PCOS patients will permit a better understanding of the syndrome and may lead to the generation of novel specific pharmacologic therapies.

Hormone-dependent gynaecological disorders: a pathophysiological perspective for appropriate treatment

Hormonal changes are involved in several gynaecological disorders. Correct functioning of the hypothalamus-pituitary-ovarian (HPO) axis is critical for ovulatory function, as well as the growth and differentiation of uterine tissue (myometrium and endometrium). However, the correct functioning of other endocrine glands (thyroid, adrenal cortex, pancreas) is also crucial for correct reproductive function. Genes and environmental factors have an influence on women's fertility through their effect on hormonal function. Consequently, dysfunction of the HPO axis and/or other endocrine systems may cause infertility and gynaecological disorders. The pathogenetic basis can be used to help make the correct clinical decision for treating these diseases. Disturbances related to the menstrual cycle, i.e. amenorrhoea, polycystic ovary syndrome (PCOS) and premenstrual syndrome (PMS), have a close correlation with hypo- or hypersecretion of hormones of the HPO axis. The roles of hypothalamic neurohormones and neurotransmitters in the various forms of amenorrhoea and PMS are well established. PCOS has a complex endocrine/metabolic origin, so a variety of hormonal treatments have been proposed. Hormone derangement has also been proposed as the cause of endometriosis and uterine fibroids. These disorders do not have hyper- or hyposecretion of reproductive hormones, but hyperactivity of oestrogen receptors coupled with a genetic predisposition. The relevance of the endocrine changes is confirmed by the clinical effectiveness of hormonal treatments. In order to establish the correct treatment approach in gynaecological disorders, it is important to understand the endocrine pathophysiology.

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

Polycystic ovary syndrome (PCOS) affects 5-10% of women at reproductive age, and is the most common reason for hyperandrogenism and chronic anovulation. Some patients with PCOS are insulin-resistant. Also, lowered sex hormone-binding globulin (SHBG) concentration is usually observed. As a consequence, the amount of free and biologically active androgens increases. This implies that, by improving insulin and carbohydrate metabolism, metformin administration in PCOS patients could indirectly contribute to increase SHBG concentration. The aim of the present study was to assess the effects of metformin treatment in PCOS patients both with and without insulin resistance. Thirty-six patients completed treatment. Body mass index (BMI) was considerably reduced after therapy. Statistically significant decreases were noted in luteinizing hormone (LH) and fasting insulin concentrations and the free androgen index (FAI), and significant increases in follicle-stimulating hormone (FSH)/LH ratio and SHBG concentration. In the insulin-resistant group, BMI and fasting insulin concentrations were reduced considerably after treatment, and SHBG increased slightly. In the group of patients without insulin resistance, BMI, LH and FAI showed significant reductions, and FSH/LH and SHBG considerable increases. Considering the favorable effects of metformin treatment in PCOS patients both with insulin resistance and without it, it is purposeful to use this drug in both groups of women.

Metformin and polycystic ovary syndrome

PURPOSE OF REVIEW

The aim of this article is to describe the role of insulin resistance in the etiology of polycystic ovary syndrome and to review the results of treatment with the insulin sensitizing drug metformin.

RECENT FINDINGS

Polycystic ovary syndrome is a heterogeneous combination of clinical, hormonal, and reproductive abnormalities associated with insulin resistance and increased cardiovascular risk factors. Reduction of hyperinsulinism and improvement of insulin sensitivity with metformin has been reported to ameliorate these abnormalities in many, but not all studies, with few adverse effects.

SUMMARY

Metformin may be the drug of first choice for most, if not all women with polycystic ovarian syndrome, either alone or in combination with other treatments. Further investigation is necessary to determine the optimal dose and duration of treatment necessary to maximize response.

Metformin administration is more effective when non-obese patients with polycystic ovary syndrome show both hyperandrogenism and hyperinsulinemia

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common endocrine disease that is frequently observed to be related to increased insulin resistance independent of body weight. The use of insulin-sensitizer compounds, such as metformin, permits great improvement of such metabolic abnormality, restoring ovarian function and gonadal steroid synthesis and reducing insulin resistance.

AIM

On this basis we aimed to evaluate a group of non-obese amenorrheic PCOS patients before and after 6 months of metformin administration (500 mg orally twice daily) to better understand upon which basis of clinical and endocrine parameters metformin administration might be chosen as a putative therapeutic tool.

METHOD

A group of non-obese PCOS patients (n = 42) was enrolled after informed consent. They underwent an oral glucose tolerance test for insulin, glucose and C-peptide levels and provided blood samples for determination of plasma levels of luteinizing hormone (LH), follicle-stimulating hormone, prolactin, estradiol, androstenedione, 17-hydroxyprogesterone, insulin, cortisol and testosterone levels on two occasions: before and on day 7 of the first menstrual cycle occurring after the 5th month of treatment.

RESULTS

Plasma LH, estradiol, insulin and C-peptide were decreased significantly by metformin treatment in the entire group of PCOS patients. When subdividing PCOS patients according to insulin sensitivity (i.e. hyper- and normoinsulinemic subjects), a greater rate of positive endocrine changes was observed in hyperinsulinemic patients and the highest rate was observed in hyperinsulinemic hyperandrogenic subjects. Menstrual cyclicity was recovered in all patients under treatment.

CONCLUSIONS

Our data show that metformin modulates ovarian function and greatly affects LH secretion through reduction of the hyperandrogenic condition. The highest rate of endocrine changes was observed in the hyperinsulinemic hyperandrogenic non-obese PCOS patients. Our study demonstrates that metformin administration is more appropriate in hyperinsulinemic hyperandrogenic non-obese PCOS patients.

Steroidogenic alterations and adrenal androgen excess in PCOS

BACKGROUND

This cross-sectional study was undertaken to improve our understanding of the steroidogenic alterations leading to adrenal hyperandrogenism in polycystic ovarian syndrome (PCOS).

METHODS

Two-hundred and thirty-four women with clinical and biochemical features suggestive of PCOS underwent metabolic and hormonal evaluation. We used the androstenedione/DHEAS ratio as a surrogate for the level of ovarian 3betaHSD activity. We then selected the 90th percentile for the ratio in those with elevated DHEAS (>9 micromol/l) as the cut-off level beyond which excess DHEAS production will be minimized by excess ovarian 3betaHSD activity. This cut-off level was at a ratio of 1.5 and all PCOS women were then divided into two groups, the higher (>1.5) being the group with excess ovarian 3betaHSD activity. We hypothesized that women with a high ratio would be unlikely to have DHEAS excess due to the rapid conversion of DHEA to androstenedione. Those with a low ratio (concordant ovarian and adrenal steroidogenesis) could then either have high DHEAS or normal DHEAS, depending on whether CYP17 activity was higher or lower respectively.

RESULTS

Insulin resistance was found to be associated with decreased CYP17 activity while irregular cycles and neuroendocrine dysfunction were determined to be associated with higher ovarian 3betaHSD activity.

CONCLUSION

Adrenal androgen excess in PCOS seems to be related to insulin sensitivity as well as decreased activity of 3betaHSD, the latter being preferentially present in those women with regular cycles or without neuroendocrine dysfunction.

Effects of metformin on inappropriate LH release in women with polycystic ovarian syndrome and insulin resistance

The role of hyperinsulinaemia in neuroendocrine abnormalities in polycystic ovarian syndrome (PCOS) is controversial. The present study applied frequent blood sampling to assess the response of LH to metformin treatment in insulin-resistant women with PCOS. Thirteen predominantly overweight women with PCOS were studied before and after treatment with 1.5 g/day metformin for 3 months. Serum LH and testosterone were measured every 10 min for 10 h; LH was measured for an additional 2 h after gonadotrophin-releasing hormone (GnRH) administration. LH pulses were characterized by cluster analysis, secretory LH episodes by a deconvolution procedure, and synchronicity of paired LH-testosterone concentrations by lag-specific cross-correlation. After treatment, basal LH concentrations, amplitude of LH pulses, LH secretory amplitude, response to exogenous GnRH, and basal testosterone concentrations significantly decreased in seven patients, whereas in the remaining women these parameters remained unaltered. Before treatment, decreased coordinate LH and testosterone release was manifested by all patients; metformin treatment led to re-establishment of the feed-back control of testosterone on LH secretory rates by -20 to 0 min. Treatment did not modify the glucose:insulin ratio or serum insulin concentrations. In conclusion, administration of metformin allowed the identification of two subsets of PCOS women in whom neuroendocrine abnormalities may improve independently of the presence of insulin resistance or hyperinsulinaemia.

Streptozotocin-induced diabetes in the rat is associated with changes in vaginal hemodynamics, morphology and biochemical markers

Background

Diabetes is associated with declining sexual function in women. However, the effects of diabetes on genital tissue structure, innervation and function remains poorly characterized. In control and streptozotocin-treated female rats, we investigated the effects of diabetes on vaginal blood flow, tissue morphology, and expression of arginase I, endothelial nitric oxide synthase (eNOS) and cGMP-dependent protein kinase (PKG), key enzymes that regulate smooth muscle relaxation. We further related these changes with estrogen receptor alpha (ERα) and androgen receptor (AR) expression.

Results

In addition to significantly elevated blood glucose levels, diabetic rats had decreased mean body weight, lower levels of plasma estradiol, and higher plasma testosterone concentration, compared to age-matched controls. Eight weeks after administration of buffer (control) or 65 mg/kg of streptozotocin (diabetic), the vaginal blood flow response to pelvic nerve stimulation was significantly reduced in diabetic rats. Histological examination of vaginal tissue from diabetic animals showed reduced epithelial thickness and atrophy of the muscularis layer. Diabetic animals also had reduced vaginal levels of eNOS and arginase I, but elevated levels of PKG, as assessed by Western blot analyses. These alterations were accompanied by a reduction in both ERα and AR in nuclear extracts of vaginal tissue from diabetic animals.

Conclusion

In ovariectomized (estrogen deficient) animals, previous reports from our lab and others have documented changes in blood flow, tissue structure, ERα, arginase I and eNOS that parallel those observed in diabetic rats. We hypothesize that diabetes may lead to multiple disruptions in sex steroid hormone synthesis, metabolism and action. These pathological events may cause dramatic changes in tissue structure and key enzymes that regulate cell growth and smooth muscle contractility, ultimately affecting the genital response during sexual arousal.

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

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common endocrine disease that is observed frequently to be related to increased insulin resistance. The use of insulin-sensitizer compounds, such as metformin, permits great improvement of such metabolic abnormality and the restoration of normal ovarian function. Metformin administration reduces insulin resistance and androgen production both from the ovary and adrenal gland.

AIM

On this basis we aimed to evaluate a group of non-obese amenorrheic PCOS patients before and after 6 months of metformin administration (500 mg per os twice daily) to better understand what changes might be induced by metformin on adrenal and ovarian function and in terms of temporal coupling of the pulsatile profiles of luteinizing hormone (LH), cortisol and allopregnanolone, the latter representative of the neurosteroid family.

METHOD

A group of non-obese PCOS patients (n = 8) was enrolled after informed consent and underwent to a pulsatility study for LH, cortisol and allopregnanolone, and an oral glucose tolerance test before and on day 7 of the first menstrual cycle occurring after the 5th month of treatment.

RESULTS

Plasma androgen levels were decreased significantly by metformin treatment, as were plasma LH and allopregnanolone levels and insulin resistance. Metformin administration decreased LH pulse amplitude but not pulse frequency. On the contrary, cortisol and allopregnanolone showed a significant change in pulse frequency. When temporal coupling was tested between pulsatile profiles of LH or cortisol with allopregnanolone, cortisol pulses were temporally coupled to allopreganolone peaks both before and under metformin administration while LH pulses were temporally coupled to allopreganolone secretory peaks only under metformin treatment.

CONCLUSIONS

Our data demonstrate that metformin administration modulates LH secretion as well as cortisol and allopregnanolone pulsatile release. In addition, the results demonstrate that adrenal and ovarian steroidogenic activity is greatly modulated by any change in insulin sensitivity.

The effects of rosiglitazone and metformin on insulin resistance and serum androgen levels in obese and lean patients with polycystic ovary syndrome

AIM

The aim of this study was to assess the effects of metformin and rosiglitazone on insulin resistance and serum androgen levels in both obese and lean patients with polycystic ovary syndrome (PCOS).

MATERIALS AND METHODS

Forty lean [body mass index (BMI) < 25 kg/m2] and 40 overweight and obese (BMI > 25 kg/m2) patients were included in the study. Waist and hip measurements, serum sex steroid levels, insulin response to 75-g oral glucose tolerance test, fasting insulin, fasting C-peptide levels and homeostasis model assessment of insulin resistance (HOMA-IR) were determined in all patients. The degree of hirsutism was determined by the Ferriman-Gallwey scoring system. Patients were divided into two groups, with 40 (20 overweight and obese; 20 non-obese) patients each. One group was treated with metformin (MET group) 850 mg bid while the other received rosiglitazone (ROSI group) 4 mg/day for 12 weeks. All measurements were repeated at the end of this period.

RESULTS

After the 12-week treatment period, HOMA-IR, area under the curve of insulin, fasting insulin and C-peptide levels were observed to have be decreased significantly in all groups. The decrease in the parameters mentioned above was similar in the four groups. The serum levels of free testosterone, androstenedione and DHEA-S decreased in all groups, but the decrease was statistically significant only in the ROSI groups. Within the lean MET group one patient became pregnant and was hence excluded from the final data analysis. Menstruations became regular after metformin therapy in 41.6% of lean and 35.7% of obese patients who had menstrual disturbance prior to the study. Rosiglitazone therapy improved menstrual disturbance in 61.5 % of lean and 53.8% of obese patients.

CONCLUSIONS

Our data showed that both metformin and rosiglitazone increased insulin sensitivity in obese patients with PCOS as expected, and in lean patients as well. Rosiglitazone seemed to be more effective in decreasing the androgen levels and in achieving slightly greater improvement in menstrual disturbance than metformin.

Does plasma insulin level affect ovarian response to exogenous administration of follicle-stimulating hormone in women without polycystic ovary syndrome?

BACKGROUND

Raised insulin levels have been shown to contribute to ovarian overproduction of androgens. Hyperinsulinemia, usually associated with polycystic ovary syndrome (PCOS), brings about greater ovarian endocrine and morphological responses to ovulation induced by follicle-stimulating hormone (FSH). This indicates that elevated levels of insulin play a role in the endocrine and paracrine control of the ovaries.

OBJECTIVE

The aim of the present study was to investigate whether basal insulin levels influence ovarian response to FSH in healthy women (non-PCOS) undergoing assisted reproduction by in vitro fertilization-embryo transfer (IVF-ET).

METHODS

The study included 36 consecutive women, 27-45 years old, undergoing IVF-ET for tubal-factor or male-factor infertility. Serum insulin levels were determined on the day of administration of gonadotropin-releasing hormone analog (GnRHa) and on the first day of FSH administration.

RESULTS

Mean insulin levels were 6 +/- 3 and 7 +/- 3 microU/ml on the day of GnRHa and FSH administration, respectively. No correlations were found between basal insulin level, days of treatment, total FSH dose, estradiol level and the number of oocytes retrieved.

CONCLUSIONS

The results of the present study show that normal levels of insulin do not seem to influence ovarian response to FSH in non-PCOS women. In all patients included in our study, serum insulin levels did not correlate with IVF stimulation data (days of stimulation, total FSH dose) nor with IVF-ET outcome. Thus the study demonstrates that, in patients who are not insulin-resistant, insulin does not correlate with ovarian response to FSH administration.

The effects of rosiglitazone and metformin on menstrual cyclicity and hirsutism in polycystic ovary syndrome

OBJECTIVE

The aim of the present study was to assess the effects of metformin and rosiglitazone on menstrual cyclicity and hirsutism in patients with polycystic ovary syndrome (PCOS).

MATERIALS AND METHODS

Ninety-six patients were included in the study. Serum sex steroids, serum fasting glucose and insulin levels, and insulin response to a 75-g oral glucose tolerance test were assessed in all patients. Menstrual cyclicity, with recording of menses in the 6-month periods before the study and during treatment, was evaluated in each patient. Patients were divided into two groups: one was treated with metformin (MET group, n = 48), while the other received rosiglitazone (ROSI group, n = 48). At baseline and after 24 weeks of treatment all patients underwent hormonal and clinical assessments, including body mass index (BMI), waist and hip measurements and Ferriman - Gallwey (FG) scores.

RESULTS

Of the 96 patients included in the study, 88 (91.7%) were able to complete it and yielded data for analyses. After the 24-week treatment period, fasting insulin levels and area under the curve for serum insulin decreased significantly, while the glucose/insulin ratio increased in both groups. The degree of reduction in serum free testosterone and androstenedione levels was similar in the two groups. The decreases in luteinizing hormone/follicle-stimulating hormone ratio and serum dehydroepiandrosterone sulfate levels were significantly greater in the ROSI group compared with the MET group. BMI increased in the ROSI group, while it decreased in the MET group. In patients with menstrual disturbance treated with rosiglitazone, menstrual cycles became regular in 87.8%, while improvement occurred in 79.3% of the patients treated with metformin. FG score decreased in both ROSI and MET groups, but the degree of decrease was significantly greater in the ROSI group than in the MET group.

CONCLUSION

Our data show that both metformin and rosiglitazone improve ovarian function and hirsutism in patients with PCOS. Rosiglitazone appears better than metformin in the treatment of hirsutism and has better patient tolerance.

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.

A randomized controlled trial evaluating metformin pre-treatment and co-administration in non-obese insulin-resistant women with polycystic ovary syndrome treated with controlled ovarian stimulation plus timed intercourse or intrauterine insemination

BACKGROUND

There are few data in the literature regarding the utility of metfomin before and during gonadotrophin administration in women with polycystic ovary syndrome (PCOS). The aim of the present study was to assess the effect of the pre-treatment and co-administration of metformin in infertile PCOS women treated with controlled ovarian stimulation (COS) followed by timed intercourse (TI) or intrauterine insemination (IUI).

METHODS

Seventy insulin-resistant primary infertile women with PCOS were randomized to receive metformin cloridrate (850 mg twice daily; group A) or placebo tablets (two tablets daily; group B) for 3 months. Three trials of COS using highly purified urinary FSH (hpFSH) plus TI/IUI were performed. Number of ampoules of gonadotrophin used, duration of the ovarian stimulation, cycle cancellation, ovulation, pregnancy, abortion, live birth, mono-ovulatory cycles, multiple pregnancies and ovarian hyperstimulation syndrome (OHSS) rates were assessed.

RESULTS

No difference between groups was detected in ovulation, cycle cancellation, pregnancy, abortion, live birth, multiple pregnancies and OHSS rates. The mono-ovulatory cycle rates were significantly (P = 0.002) more frequent in group A than in group B, whereas the days of stimulation for non-cancelled cycles and the number of vials of gonadotrophins used were significantly (P < 0.001) higher in group A than in group B.

CONCLUSION

In insulin-resistant women with PCOS, metformin pre-treatment and co-administration with hpFSH increases the mono-ovulatory cycles.

Un rôle pour PPARγ dans la reproduction ?

Synthetic molecules of the glitazone family are currently used in the treatment of type II diabetes. Glitazones also improve secondary pathologies that are frequently associated with insulin resistance such as the polycystic ovary syndrome (PCOS). Glitazones bind to the peroxysome proliferator-activated receptor gamma (PPARgamma), a nuclear receptor which is highly expressed in adipose tissue. PPARgamma also binds natural ligands such as long-chain fatty acids. Recently, several groups have shown that PPARgamma is also highly expressed in ovarian granulosa cells, and that glitazones are able to modulate in vitro granulosa cell proliferation and steroidogenesis in several species. These recent data raise new questions concerning the underlying mechanism of the effect of glitazones on PCOS. One might hypothesize, as for other << glucophage >> molecules such as metformin, that it is the general improvement of glucose metabolism and insulin sensitivity by glitazones which indirectly, and via an unknown mechanism, ameliorates ovarian functionality. The data discussed here suggest now an alternative possibility, that glitazones act directly at the ovarian level. Moreover, PPARgamma also seems to play a key role in the maturation of the placenta. In particular, inactivation of PPARgamma in mice is lethal, since the foetus is unable to develop because of alterations of placental maturation. In women, the activation of PPARgamma in placenta leads to an increase of placental hormone secretion. Overall, these results raise some questions about the role of natural ligands of PPARgamma such as long chain fatty acids on female fertility and the interactions between energy metabolism and reproduction in general.

Insulin-sensitizing agents: use in pregnancy and as therapy in polycystic ovary syndrome

Treatment with insulin-sensitizing agents is a relatively recent therapeutic strategy in women with polycystic ovary syndrome (PCOS) and insulin resistance. The key areas addressed in this review include PCOS and the development of type 2 diabetes mellitus and gestational diabetes, as well as the use of insulin-sensitizing agents, particularly metformin, in the management of infertility in obese and non-obese PCOS women. Treatment with metformin in PCOS women undergoing IVF and the use of metformin during gestation will be discussed. The challenge for the health care professional should be the appropriate utilization of pharmacotherapies to improve insulin sensitivity and lower circulating insulin levels resulting in beneficial changes in PCOS phenotype. Further research into the potential role of other insulin-sensitizing agents, such as pioglitazone and rosiglitazone, in the treatment of infertile women with PCOS is needed.

Does metformin modify ovarian responsiveness during exogenous FSH ovulation induction in normogonadotrophic anovulation? A placebo-controlled double-blind assessment

OBJECTIVE

To assess whether the addition of metformin to gonadotrophin ovulation induction in insulin-resistant, normogonadotrophic, anovulatory women alters ovarian responsiveness to exogenous FSH.

DESIGN

Placebo-controlled double-blind assessment in an academic hospital.

RESULTS

After a progestagen withdrawal bleeding, patients were randomised for either metformin (n = 11) or placebo (n = 9) treatment. In cases of absent ovulation, exogenous FSH was subsequently administered to induce ovulation. Only during metformin treatment did body mass index and androgen (androstenedione and testosterone) levels decrease, whereas FSH and LH levels increased significantly. In the metformin group, a single patient ovulated before the initiation of exogenous FSH. Significantly more monofollicular cycles and lower preovulatory oestradiol concentrations were observed in women receiving FSH with metformin compared with FSH alone.

CONCLUSIONS

Metformin co-treatment in a group of insulin-resistant, normogonadotrophic, anovulatory patients resulted in normalization of the endocrine profile and facilitated monofollicular development during the FSH induction of ovulation.

The importance of IRS-1 Gly972Arg polymorphism in evaluating the response to metformin treatment in polycystic ovary syndrome

BACKGROUND

Recent evidence suggests that one of the modes of action of metformin may be through phosphorylation of the insulin receptor and insulin receptor substrates. With this in mind, we supposed that the G972A variant of insulin receptor substrate-1 (IRS-1) may modulate the response to metformin treatment in women with polycystic ovary syndrome (PCOS).

METHODS

This preliminary study involved 60 randomly selected women with PCOS. All patients received dietary instructions and metformin 500 mg three times daily for 6 months. Main outcome measures were androgen levels, parameters of glucose and insulin metabolism and anthropometric variables. After a second evaluation of the patients at 6 months, they were genotyped for the Gly972Arg variant of the IRS-1 gene.

RESULTS

Metformin had differential effects on fasting insulin levels, insulin resistance as demonstrated by homeostasis model assessment (HOMA), LH, total testosterone, dehydroepiandrosterone sulphate and free testosterone index on the basis of IRS genotype. The response to metformin therapy in other parameters was not different according to IRS genotype.

CONCLUSION

There was a differential effect of metformin therapy in PCOS women on the basis of IRS genotype. This study may call attention to the importance of molecular markers in the management of women with PCOS.

Effects of metformin combined with cyproterone acetate on clinical features, endocrine and metabolism of non-obese women with polycystic ovarian syndrome

In order to explore the effects of metformin combined with cyproterone acetate (CPA) on the clinical features, endocrine and metabolism of the patients with polycystic ovarian syndrome (PCOS), 50 cases of non-obese PCOS were randomly subjected to CPA (CPA treatment group, n = 25) and CPA+ metformin (n = 25) treatment for 6 months. Before and after treatment the body mass index (BMI), waist : hip ratio (WHR), ovarian volume, serum gonadotrophin, androgen and sex hormone-binding globulin (SHBG) levels, and fasting lipid, glucose and insulin levels were measured. The results showed that all of the parameters in two groups were similar before treatment. After treatment for 6 months in the CPA+ metformin group, BMI and WHR were significantly decreased, while insulin sensitivity was significantly decreased as Compared with those before treatment. In CPA group, no significant changes were found before and after treatment. Combined use of CPA and metformin could result in the reduction of serum androstenedione and increases of serum SHBG levels as compared with the CPA treatment alone. It was concluded that combined use of CPA and metformin could improve the insulin sensitivity, and further suppress the hyperandrogenism in non-obese women with PCOS.

M�llerian-inhibiting substance in women with polycystic ovary syndrome: Relationship with hormonal and metabolic characteristics

The aim of the present study was to examine the relationship between Mullerian-inhibiting substance (MIS) levels and metabolic characteristics in women with polycystic ovary syndrome. Increased ovarian MIS production may exert a paracrine negative control on follicle growth sufficiently to prevent selection of a dominant follicle.

The pathophysiology of polycystic ovary syndrome: trying to understand PCOS and its endocrinology

The pathophysiology of the polycystic ovary syndrome (PCOS) encompasses inherent ovarian dysfunction that is strongly influenced by external factors, such as disturbances of the hypothalamic-pituitary-ovarian axis and hyperinsulinaemia. Exaggerated gonadotrophin releasing hormone (GnRH) pulsatility results in hypersecretion of luteinising hormone (LH), which has effects both on ovarian androgen production and oocyte development. Disturbed ovarian-pituitary and hypothalamic feedback accentuates the 0gonadotrophin abnormalities. Hyperinsulinaemia is secondary both to insulin resistance at the periphery and to abnormal pancreatic beta cell function. PCOS runs in families and a number of genetic abnormalities appear to result in features of the syndrome and account for the heterogeneity of the symptoms. Environmental influences, such as nutrition and lifestyle, further influence expression of the syndrome.

Effect of metformin on the clinical and metabolic assessment of women with polycystic ovary syndrome

A longitudinal prospective study was conducted in 21 women with polycistic ovary syndrome (PCOS), aged 27.20 +/- 5.02 years and treated with metformin (1500 mg/day)for 8 weeks. The patients were assessed for spontaneous menstruation, weight, body mass index (BMI), waist circumference, waist/hip ratio (WHR), glucose and insulin concentrations under fasting conditions and after a 75-g glucose tolerance test, lipid profile, testosterone, androstenedione, dehydroepiandrosterone sulfate, sex-hormone binding globulin (SHBG), and insulin-like growth factor (IGF)-I. Spontaneous menstruation was observed in 81% of the women treated with metformin, with no changes in weight or BMI. Waist measurement and the WHR were reduced. The quantitative insulin sensitivity check index (QUICKI) improved from 0.33 +/- 0.03 to 0.35 +/- 0.04 (p < 0.005), and serum total cholesterol and low-density lipoprotein-cholesterol were reduced, while high-density lipoprotein-cholesterol was increased. Serum testosterone concentrations were also reduced. There were no differences in serum triglycerides, SHBG or IGF-I. The occurrence of spontaneous menstruation and changes in the pattern of body fat distribution, the reduction in serum testosterone concentrations, the improvement in lipid profile and the reduction of insulinemia with the use of metformin permit us to conclude that treatment with this drug is of benefit to women with PCOS.

Exaggerated 17-hydroxyprogesterone response to intravenous infusions of recombinant human LH in women with polycystic ovary syndrome

Studies using pharmacological gonadotropin stimulation suggest that ovarian steroidogenesis is abnormal in the polycystic ovary syndrome (PCOS). We assessed ovarian steroid secretion in response to near-physiological gonadotropin stimuli in 12 ovulatory controls and 7 women with PCOS. A gonadotropin-releasing hormone-receptor antagonist (ganirelix, 2 mg sc) was given to block endogenous LH secretion, followed by dexamethasone (0.75 mg orally) to suppress adrenal androgen secretion. After ganirelix injection (12 h), intravenous infusions of recombinant human LH (0, 10, 30, 100, and 300 IU; each over 8 min) were administered at 4-h intervals in a pseudorandomized (highest dose last) manner. Plasma LH, 17-hydroxyprogesterone (17-OHP), androstenedione, and testosterone were measured concurrently. LH dose-steroid response relationships (mean sex-steroid concentration vs. mean LH concentration over 4 h postinfusion) were examined for each subject. Linear regression of 17-OHP on LH yielded a higher (mean +/- SE) slope in PCOS (0.028 +/- 0.010 vs. 0.005 +/- 0.005, P < 0.05), whereas extrapolated 17-OHP at zero LH was similar. The slopes of other regressions did not differ from zero in either PCOS or controls. We conclude that near-physiological LH stimulation drives heightened 17-OHP secretion in patients with PCOS, suggesting abnormalities of early steps of ovarian steroidogenesis. With the exception of 17-OHP response in PCOS, no acute LH dose-ovarian steroid responses were observed in controls or PCOS. Defining the precise mechanistic basis of heightened precursor responsiveness to LH in PCOS will require further clinical investigation.