Insulin, leptin, IGF-I and insulin-dependent protein concentrations after insulin-sensitizing therapy in obese women with polycystic ovary syndrome

Insulin-like growth factor binding protein-1 and insulin in polycystic ovary syndrome: a systematic review and meta-analysis

Background

Insulin-like growth factor binding protein-1 (IGFBP-1) is considered a decline in polycystic ovary syndrome (PCOS), but it remains controversial that whether such reduction is attributed to obesity.

Aims

This systematic review aims to explore whether IGFBP-1 is reduced in PCOS, and whether such reduction is associated with obesity.

Results

Our pooled study included 12 studies with a total of 450 participants. IGFBP-1 levels in PCOS were significantly lower than that in non-PCOS (SMD (95%CI)=-0.49(-0.89, -0.09), P=0.02). No significant difference in IGFBP-1 levels between patients with or without PCOS classified by BMI. Whilst, stratification by PCOS status revealed a significant decrease in IGFBP-1 in overweight (SMD (95%CI)=-0.92(-1.46, -0.37), P=0.001). When comparing fasting insulin in the same way, PCOS patients had significantly elevated fasting insulin level but not statistically declined IGFBP-1 after classified by BMI.

Conclusion

This meta-analysis provides evidence that the decrease of IGFBP-1 in PCOS was more strongly influenced by comorbid obesity than by PCOS itself. Additionally, contrast to previous findings that insulin significantly suppresses IGFBP-1, our results suggested that the suppression of PCOS-related hyperinsulinemia on IGFBP-1 seemed diminished. Overall, our work may provide a novel perspective on the mechanism between insulin and IGFBP-1 underlying PCOS development.

The Effect of a Very-Low-Calorie Diet (VLCD) vs. a Moderate Energy Deficit Diet in Obese Women with Polycystic Ovary Syndrome (PCOS)-A Randomised Controlled Trial

We performed an open-label, randomised controlled trial to compare the effects of a very-low-calorie diet (VLCD) vs. moderate energy deficit approach on body weight, body composition, free androgen index (FAI), and metabolic markers in obese women with polycystic ovary syndrome (PCOS). Forty eligible patients were randomly assigned to a VLCD (n = 21) or a conventional energy deficit approach (n = 19) over the same period. After eight weeks, both groups experienced significant weight loss; however, this was greater in the VLCD arm (-10.9% vs. -3.9%, p < 0.0001). There was also a trend towards a reduction in FAI in the VLCD group compared to the energy deficit group (-32.3% vs. -7.7%, p = 0.07). In the VLCD arm, two women (18%) had a biochemical remission of PCOS (FAI < 4); this was not the case for any of the participants in the energy deficit arm. There was a significant within-group increase in the sex-hormone-binding globulin (p = 0.002) and reductions in fasting blood glucose (p = 0.010) and waist to hip ratio (p = 0.04) in the VLCD arm, but not in the energy deficit arm. The VLCD resulted in significantly greater weight reduction and was accompanied by more pronounced improvements in hyperandrogenaemia, body composition, and several metabolic parameters in obese women with PCOS as compared to the energy deficit approach.

Association of Insulin-Like Growth Factor-1 With Polycystic Ovarian Syndrome: A Systematic Review and Meta-analysis

OBJECTIVE

Circulating concentration of insulin-like growth factor (IGF)-1 in patients with polycystic ovary syndrome (PCOS) is still unclear. Therefore, we aimed to investigate the association of IGF-1 with PCOS through this meta-analysis.

METHODS

Literature search was conducted through PubMed, Embase, Web of Science, Cochrane Library, and China National Knowledge Infrastructure (up to July 2022). A manual search was performed on the references of related original research. Then, we applied the random-effects model to evaluate the overall effect size by calculating the standard mean difference and its 95% CI. Subgroup analyses were used to explore the sources of heterogeneity. In addition, a sensitivity analysis was performed and publication bias was assessed.

RESULTS

Twenty studies were included in this meta-analysis involving 657 individuals: 362 patients with PCOS and 295 normal controls. The results of meta-analysis showed that serum IGF-1 levels were significantly higher in patients with PCOS than in controls (standard mean difference, 0.89; 95% CI, 0.34-1.45; P = .002). The final pooled data were determined by the random-effects model because a significant high heterogeneity (I² = 89%) was found. A subgroup analysis based on body mass index showed that elevated IGF-1 level was associated with normal-weight and overweight patients in the PCOS group, but there was no significant association with obesity. The sensitivity analysis indicated that no individual study significantly affected the overall pooled result and no publishing bias was observed.

CONCLUSION

These data suggest that elevated serum IGF-1 levels may not be a major cause of PCOS pathogenesis. Body mass index may be a major determinant of serum IGF-1.

Effect of Metformin on Anthropometric Measurements and Hormonal and Biochemical Profile in Patients with Prediabetes

OBJECTIVES

Metformin is the most widely preferred first-line oral antidiabetic agent that results in clear benefits in blood sugar regulation and diabetes-related complications. This study is aimed at assessing the effect of metformin on anthropometric, hormonal, and biochemical parameters in patients with prediabetes or insulin resistance.

METHODS

A prepoststudy was conducted among 52 patients with prediabetes or insulin resistance who met the inclusion criteria. Weight, body mass index (BMI), and waist circumference were measured before and 12 months after metformin treatment. Serum concentrations of sex steroids, gonadotropins, and lipids were also assessed. Homeostasis model assessment (HOMA) index and quantitative sensitivity check (QUICKI) index scores were calculated before metformin treatment and after 12 months of use.

RESULTS

After 12 months of metformin treatment, female patients had significant reduction in weight, BMI, and waist circumference after adjusting for age. Metformin use for 12 months resulted in significant reduction in mean fasting blood glucose and HbA1c in females only. Total cholesterol decreased significantly among men only and serum HDL-C showed a significant rise among females only. Serum LDL-C and triglycerides did not change significantly in females and males. Our study did now significant changes in ACTH and cortisol levels in both females and males after metformin treatment. Metformin use resulted in significant increase in luteinizing hormone (LH) and progesterone levels in males, while it was associated with significant increase in prolactin, follicular stimulating hormone (FSH), and dehydroepiandrostenedione-sulphate (DHEA-S) levels and significant decrease in total testosterone level in females.

CONCLUSION

Metformin treatment in females with prediabetes reduces BMI, waist circumference, fasting blood glucose, and HbA1c. The changes in the studied parameters differed significantly according to sex.

Weight Management Interventions in Women with and without PCOS: A Systematic Review

Polycystic ovary syndrome (PCOS) is a common endocrinopathy among women associated with reproductive, metabolic and psychological features. While weight management is recommended as first-line treatment, it is unclear if women with PCOS achieve similar benefits as women without PCOS. This systematic review thus aimed to compare the efficacy of weight management interventions in women with and without PCOS. Databases were searched until May 2017. The primary outcome was weight and anthropometric, reproductive, metabolic and psychological measures were secondary outcomes. Of 3264 articles identified, 14 studies involving n = 933 (n = 9 high and n = 5 moderate risk of bias) met the inclusion criteria. No statistically significant differences in weight or weight loss following the intervention were found between women with and without PCOS in five studies, with the remaining studies not comparing the difference in weight or weight loss between these groups. Secondary outcomes did not differ significantly between the two groups. This review identified that there is a paucity of high quality research in this area and that more rigorous research is needed.

Metformin vs myoinositol: which is better in obese polycystic ovary syndrome patients? A randomized controlled crossover study

CONTEXT

Due to the central role of metabolic abnormalities in the pathophysiology of polycystic ovary syndrome (PCOS), insulin sensitizing agents have been proposed as a feasible treatment option.

OBJECTIVE

To investigate which is the more effective between metformin and myoinositol (MYO) on hormonal, clinical and metabolic parameters in obese patients with PCOS.

STUDY DESIGN

Crossover randomized controlled study.

PATIENTS

Thirty-four PCOS obese women (age: 25·62 ± 4·7 years; BMI: 32·55 ± 5·67 kg/m² ) were randomized to receive metformin (850 mg twice a day) or MYO (1000 mg twice a day) for 6 months. After a 3 month washout, the same subjects received the other compound for the following 6 months.

MEASUREMENTS

Ultrasonographic pelvic examinations, hirsutism score, anthropometric and menstrual pattern evaluation, hormonal profile assays, oral glucose tolerance test (OGTT) and lipid profile at baseline and after 6 months of treatment were performed.

RESULTS

Both metformin and MYO significantly reduced the insulin response to OGTT and improved insulin sensitivity. Metformin significantly decreased body weight and improved menstrual pattern and Ferriman-Gallwey score. Metformin treatment was also associated with a significant decrease in LH and oestradiol levels, androgens and anti-müllerian hormone levels. None of these clinical and hormonal changes were observed during MYO administration.

CONCLUSIONS

Both treatments improved the glyco-insulinaemic features of obese PCOS patients, but only metformin seems to exert a beneficial effect on the endocrine and clinical features of the syndrome.

Impact of Treatment with Metformin on Adipocytokines in Patients with Polycystic Ovary Syndrome: A Meta-Analysis

Background

Metformin is effective for the treatment of polycystic ovary syndrome, but conflicting results regarding its effect on adipocytokine levels (adiponectin, resistin, visfatin, and leptin) in patients with polycystic ovary syndrome receiving metformin treatment have been reported. To provide high-quality evidence about the effect of metformin treatment on adipocytokines in patients with polycystic ovary syndrome, relevant studies that assessed the levels of adipocytokines (adiponectin, resistin, visfatin, and leptin) in patients with polycystic ovary syndrome receiving treatment with metformin administration were reviewed and analyzed.

Methods

A literature search was conducted in the SCI, PUBMED, EMBASE, and Elsevier databases, and personal contact was made with the authors. Standard mean differences and 95% confidence intervals were calculated and combined appropriately. To ensure synthesis of the best available evidence, sensitivity analyses were performed.

Results

A total of 34 data sets were included in 4 different outcomes, involving 744 women with polycystic ovary syndrome and adipocytokine levels measured both before and after metformin administration. Metformin treatment was associated with significantly elevated serum adiponectin concentrations (standard mean differences [95% confidence interval], −0.43 [−0.75 to −0.11]) and decreased serum leptin concentrations (0.65 [0.26 to 1.04]), whereas no significant difference in resistin level (−0.01 [−0.49 to 0.45]) or visfatin level (−0.04 [−1.55 to 1.46]) was found.

Conclusions

Metformin administration was associated with increased serum adiponectin concentrations and decreased serum leptin levels. Further study is needed to elucidate whether this apparent effect decreases the incidence of type 2 diabetes and other metabolic diseases in patients with polycystic ovary syndrome later in life.

Hormonal State Comparison (Progesterone, Estradiol, and Leptin) of Body Fat and Body Mass Indices in Mexican Women as a Risk Factor for Neonatal Physiologic Condition

STUDY OBJECTIVE

Describe the impact of teen pregnancy on later ovarian activity and metabolic hormones considering the concentration of current levels of ovarian steroids and leptin in a sample of Mexican females.

DESIGN

Cross-sectional study in the maternity of the General Hospital of Atlacomulco and campus of the Autonomous University of the State of Mexico.

PARTICIPANTS

71 women between the ages of 18 and 24, and 160 neonates seen between March 2010 and June 2012.

MAIN OUTCOME MEASURES

The measurements obtained included anthropometric body composition (bioelectrical impedance), serum hormone quantification of ovarian steroids and leptin (immunoassays), and the Apgar scores, height, and weight in neonates. Statistical analysis included ANOVA, Student, and chi-square for P < .05.

RESULTS

Adolescent mothers showed significantly lower concentrations of estradiol (P = .001) and progesterone (P = .001). However, higher levels of leptin in adolescent mothers were not statistically different compared with older mothers (P = .84). Also, leptin was correlated with all measures of adiposity. The mean birth weights (P = .001) and Apgar scores (P = .001) were lower in neonates of adolescent mothers than in neonates of adult mothers. There was no association between maternal age with the anthropometric variables studied.

CONCLUSIONS

Early reproduction represents a metabolic stress condition that modifies the long term ovarian activity and metabolic hormones, and impacts the morbidity-mortality of the mother and offspring in a later vital life cycle stage.

20 years of leptin: role of leptin in human reproductive disorders

Leptin, as a key hormone in energy homeostasis, regulates neuroendocrine function, including reproduction. It has a permissive role in the initiation of puberty and maintenance of the hypothalamic-pituitary-gonadal axis. This is notable in patients with either congenital or acquired leptin deficiency from a state of chronic energy insufficiency. Hypothalamic amenorrhea is the best-studied, with clinical trials confirming a causative role of leptin in hypogonadotropic hypogonadism. Implications of leptin deficiency have also emerged in the pathophysiology of hypogonadism in type 1 diabetes. At the other end of the spectrum, hyperleptinemia may play a role in hypogonadism associated with obesity, polycystic ovarian syndrome, and type 2 diabetes. In these conditions of energy excess, mechanisms of reproductive dysfunction include central leptin resistance as well as direct effects at the gonadal level. Thus, reproductive dysfunction due to energy imbalance at both ends can be linked to leptin.

Insulin-like growth factor binding protein-1 in PCOS: a systematic review and meta-analysis

BACKGROUND

Despite extensive research, the pathogenesis of polycystic ovary syndrome (PCOS) remains unclear. Putatively, an elevated circulating concentration of insulin inhibits the production of insulin-like growth factor binding protein-1 (IGFBP-1), thus increasing the level of free IGF-I in serum and stimulating ovarian androgen production. Decreased IGFBP-1 has been reported in PCOS and in obesity; however, there are inconsistencies in the evidence. This systematic review and meta-analysis aimed to determine whether IGFBP-1 is decreased in PCOS when controlling for the influence of BMI.

METHODS

Articles published between 1988 and 2008 were searched using MEDLINE, PubMed, SCOPUS and Web of Knowledge. Unpublished literature, trials in progress, and recent reviews were also searched. Original articles were selected by two investigators. To be included, the study must have compared serum IGFBP-1 in two populations: either PCOS versus controls, or an overweight subgroup versus the normal weight subgroup in either population. From 617 identified articles, 12 were included in the meta-analysis. Data were abstracted by two reviewers independently and standardized for errors.

RESULTS

The population difference is presented as the Weighted Mean Difference (95% CI). PCOS subjects had a significantly lower serum concentrations of IGFBP-1 compared with controls [P< 0.00001; -36.6 (-52.0, -21.2) µg/l]. Overweight PCOS subjects also had lower IGFBP-1 levels compared with normal weight PCOS subjects [P < 0.006; -30.6 (-52.3, -8.8) µg/l]. No significant difference was found between overweight PCOS patients and overweight controls [P = 0.23; -5.1 (-13.5, 3.2) µg/l] or between normal weight PCOS patients and normal weight controls [P = 0.50; -3.8 (-14.9, 7.3) µg/l]. Overweight controls had significantly lower IGFBP-1 concentrations than normal weight controls [P = 0.03; -18.0 (-34.4, - 1.5) µg/l].

CONCLUSION

These data indicate that a decreased serum level of IGFBP-1 is unlikely to be a mechanism for ovarian hyperandrogenism in PCOS. BMI may be the major determinant of serum IGFBP-1.

The adverse effects of obesity on conception and implantation

Whilst many multiparous women are obese (body mass index >30 kg/m(2)), obesity has been associated with impaired fecundity; however, the mechanism which links obesity to reduced fertility remains to be fully elucidated. Obese women, particularly those with central obesity, are less likely to conceive per cycle. Obese women suffer perturbations to the hypothalamic-pituitary-ovarian axis, menstrual cycle disturbance and are up to three times more likely to suffer oligo-/anovulation. A fine hormonal balance regulates follicular development and oocyte maturation, and it has been observed that obesity can alter the hormonal milieu. Leptin, a hormone produced by adipocytes, is elevated in obese women, and raised leptin has been associated with impaired fecundity. Obesity impairs ovulation but has also been observed to detrimentally affect endometrial development and implantation. The expression of polycystic ovary syndrome (PCOS) is regulated, in part, by weight, and so obese women with PCOS often have a more severe phenotype and experience more subfertility. Obesity also impairs the response of women to assisted conception treatments. Weight loss through lifestyle modification or bariatric surgery has been demonstrated to restore menstrual cyclicity and ovulation and improve the likelihood of conception. In this article, we will discuss the effect of obesity upon key reproductive mechanisms and its relation to fertility treatments.

Retinol-binding protein 4 in polycystic ovary syndrome--association with steroid hormones and response to pioglitazone treatment

CONTEXT

Polycystic ovary syndrome (PCOS) is frequently associated with insulin resistance.

OBJECTIVE

The aim of the study was to investigate a putative role of the adipokines retinol-binding protein 4 (RBP4), adiponectin, and visfatin in a cohort of patients with PCOS and their response to treatment with pioglitazone.

DESIGN AND SETTING

We conducted a randomized, controlled, double-blind study at a tertiary referral center.

PATIENTS AND INTERVENTIONS

Forty premenopausal women with PCOS were allocated to receive treatment with either pioglitazone (30 mg/d) or a placebo for a period of 3 months.

MAIN OUTCOME MEASURES

Serum concentrations of RBP4, adiponectin, and visfatin were determined along with metabolic and hormonal parameters before and after treatment.

RESULTS

Serum adiponectin concentrations were higher after treatment with pioglitazone (P = 0.003), whereas RBP4 levels tended to decrease (P = 0.06), and visfatin concentrations remained unchanged. We found RBP4 serum concentrations at baseline to be positively correlated with serum levels of testosterone (R = 0.446; P = 0.005), 17-OH progesterone (R = 0.345, P = 0.037), and dehydroepiandrosterone sulfate (R = 0.347; P = 0.041). However, these correlations were abolished after treatment with pioglitazone. Patients with high RBP4 levels had significantly higher hirsutism scores (P = 0.038 before and P = 0.034 after treatment). In contrast, serum adiponectin concentrations were related to parameters of impaired glucose metabolism, and no significant associations were detected for visfatin.

CONCLUSIONS

Our results suggest that RBP4 may contribute to endocrine changes and to the phenotypic manifestation of patients with PCOS because higher RBP4 concentrations are associated with higher androgen levels and higher clinical hirsutism scores independently of pioglitazone treatment. The molecular involvement of RBP4 in human steroid metabolism requires further clarification.

Is it time to test metformin in breast cancer clinical trials?

Several studies have identified an increased risk of cancer in type 2 diabetic patients and this is in accordance with the hypothesis that increased insulin levels might promote cancer. Thus, there is a great interest in exploring the possibility that antidiabetic therapies lowering insulin levels could decrease cancer incidence or cancer-related mortality. Recent observational studies have shown that metformin, an oral safe and well-tolerated insulin-sensitizer antidiabetic drug, has been associated with reduced cancer risk. Recently, several preclinical studies have evaluated the effect of metformin in vivo on nude mice and showed a significant reduction of both breast epithelial cell proliferation and protein synthesis. Further investigations in the clinical setting are well-supported by the promising results obtained thus far. At the European Institute of Oncology, the Division of Cancer Prevention and Genetics is planning to conduct a clinical trial to evaluate the activity of metformin on tumor cell proliferation in breast cancer patients undergoing surgery. It will be a presurgical randomized, double blind, placebo-controlled phase II biomarker trial: 100 histologically confirmed breast cancer patients will be randomly assigned to metformin (850 mg twice/daily) or placebo for 28+7 days till surgery to assess drug activity on tumor proliferation, as measured by Ki-67. The confirmation of the efficacy of metformin on cancer cell proliferation may lead the way to larger chemoprevention clinical trials.

The investigation and management of severe hyperandrogenism pre- and postmenopause: non-tumor disease is strongly associated with metabolic syndrome and typically responds to insulin-sensitization with metformin

BACKGROUND

An androgen-secreting tumor needs to be excluded in any woman with severe hyperandrogenism. We sought to characterize patients with biochemical hyperandrogenism in respect of tumor versus non-tumor etiologies, explore possible links between non-tumor hyperandrogenism and metabolic syndrome, and ascertain whether metformin therapy can elicit diagnostic reductions in serum testosterone (T).

PATIENTS AND METHODS

Seven-year retrospective study of all women referred to a university hospital endocrinology service with baseline T >4.0 nmol/l. Dataset comprised age, menopausal status, body mass index (BMI), presence/absence of hypertension, diabetes, acanthosis or dyslipidemia, along with changes in BMI and serum T following intervention with metformin, oophorectomy or dexamethasone. Non-tumor hyperandrogenism was defined by normalization of serum T or >40% reduction from baseline.

RESULTS

Four out of 18 cases had adrenal carcinoma that was clinically obvious at initial presentation (one virilized, three Cushingoid). The remaining 14 were characterized by metabolic syndrome (BMI: 39.9 +/- 8.1 kg/m(2)), serum T of 6.14 +/- 1.6 nmol/l, and nadir serum T following intervention of 2.2 +/- 1.04 nmol/l. Diagnostic reductions in serum T occurred in 11/12 patients treated with metformin.

CONCLUSIONS

Non-tumor hyperandrogenism with markedly elevated serum T and associated metabolic syndrome is a defined clinical entity in postmenopause as well as in premenopausal women with polycystic ovary syndrome. This has hitherto been only sparsely documented in the published literature. A fall in serum T level in response to insulin-sensitizing therapy with metformin and lifestyle change may be a reassuring indicator that such women are highly unlikely to harbor an androgen-secreting tumor.

Serum Levels of Leptin and Homocysteine in Women with Polycystic Ovary Syndrome and Its Relationship to Endocrine, Clinical and Metabolic Parameters

We examined the relationship between endocrine, clinical and metabolic parameters in 35 women (mean age 27.3 years) with polycystic ovary syndrome (PCOS) and 30 age- and body mass index-matched normal ovulatory women. In PCOS women, serum leptin, homocysteine, insulin, insulin-like growth factor-1, insulin-like growth factor binding protein-3 levels and the insulin resistance index (HOMA-IR) were significantly higher, while sex hormone-binding globulin and high-density lipoprotein cholesterol levels were lower compared with healthy women. Serum luteinizing hormone (LH), estradiol (E2), androstenedione, testosterone and dehydroepiandrosterone sulphate levels were found to be significantly higher in PCOS women compared with healthy women. The levels of E2, LH and testosterone were positively correlated with leptin levels in PCOS women. Similarly, androstenedione levels and HOMA-IR were positively correlated with homocysteine levels and insulin levels were positively correlated with LH. We conclude that increased homocysteine levels, hyperandrogenaemia, insulin resistance and impaired lipid metabolism contribute to the risk of premature atherosclerosis in PCOS women.

A randomized controlled trial of the efficacy of rosiglitazone and clomiphene citrate versus metformin and clomiphene citrate in women with clomiphene citrate-resistant polycystic ovary syndrome

OBJECTIVE

To compare the efficacy of rosiglitazone and clomiphene citrate (CC) with metformin and CC in women with CC-resistant polycystic ovary syndrome (PCOS).

DESIGN

Randomized controlled trial (RCT).

SETTING

A university teaching hospital in Jeddah, Saudi Arabia.

PATIENT(S)

Twenty-five women with CC-resistant PCOS.

INTERVENTION(S)

Twelve women were assigned to the rosiglitazone and CC group, and 13 women were assigned to the metformin and CC group for three treatment cycles. The first cycle was started on the first day of the period with either rosiglitazone (4 mg twice daily) or metformin (500 mg three times daily) and continued for three cycles. Clomiphene citrate (100 mg) from the third day for 5 days was added to each cycle.

MAIN OUTCOME MEASURE(S)

Ovulation rate, number of follicles and estradiol (E2) on day 12 of the cycle, pregnancy rate, and changes in fasting glucose, serum insulin, HbA(1C), total testosterone (T), free T, luteinizing hormone (LH), follicle-stimulating hormone (FSH), dehydroepiandrosterone sulfate (DHEAS), delta4-androstenedione (delta4-A), sex hormone-binding globulin (SHBG), insulin-like growth factor (IGF)-1, insulin-like growth factor binding protein (IGFBP)-1, and IGFBP-3.

RESULT(S)

No significant differences were found in the baseline characteristics of both groups. Ovulation rate was significantly higher in the rosiglitazone and CC group (18 out of 28 cycles [[64.3%]]) than the metformin and CC group (12 out of 33 cycles [[36.4%]]) (P=.035). Similarly, statistically significant differences were found in the number of follicles > or =14 mm in the rosiglitazone and CC group (2.2 +/- 1) compared with the metformin and CC group (1.1 +/- 0.9) (P=.02) and E2 on day 12 of the cycle in the rosiglitazone and CC group (1,991 +/- 1,389 pmol/L) compared with the metformin and CC group (548 +/- 327) (P<.001). The pregnancy rate was also higher in the rosiglitazone and CC group (6 out of 12 [[50%]] women) than the metformin and CC group (5 out of 13 [[38.5%]] women), but did not reach statistical significance (P=.58). Both groups showed no significant changes in fasting plasma glucose or HbA(1C) or IGFBP-3 values. However, in both groups, fasting serum insulin, total T, free T, LH, DHEA-S, delta4A, and IGF-1 levels decreased significantly, and SHBG and IGFBP-1 exhibited significant increases.

CONCLUSION(S)

These findings suggest that short-term use of rosiglitazone and CC is more efficacious than metformin and CC in ovulation induction in women with CC-resistant PCOS.

Serum leptin levels correlate with obesity parameters but not with hyperinsulinism in women with polycystic ovary syndrome

OBJECTIVE

To examine serum leptin concentrations in obese and lean patients with polycystic ovary syndrome (PCOS) to assess whether the changes in leptin levels are due to obesity or hormonal alterations.

DESIGN

Controlled clinical study.

SETTING

Academic research environment.

PATIENT(S)

Obese and lean women with PCOS.

INTERVENTION(S)

Blood samples were collected before and after food consumption.

MAIN OUTCOME MEASURE(S)

Serum leptin and insulin levels.

RESULT(S)

Serum leptin concentrations were significantly correlated with body mass index (r = 0.649) and also with HOMA (r = 0.535). However, after controlling for body mass index in a partial correlation analysis, no significant correlation was found between serum leptin levels and HOMA or hyperinsulinemia. While lean patients with PCOS had a significant correlation between leptin concentrations and obesity parameters, they did not show any significant correlation with insulin resistance parameters.

CONCLUSION(S)

Although leptin concentrations in women with PCOS correlate with insulin resistance/hyperinsulinemia, this is related only to obesity.

Detecting insulin resistance in polycystic ovary syndrome: purposes and pitfalls

Approximately 50% to 70% of all women with polycystic ovary syndrome (PCOS) have some degree of insulin resistance, and this hormone insensitivity probably contributes to the hyperandrogenism that is responsible for the signs and symptoms of PCOS. Although uncertainty exists, early detection and treatment of insulin resistance in this population could ultimately reduce the incidence or severity of diabetes mellitus, dyslipidemia, hypertension, and cardiovascular disease. Even if that proves to be the case, there are still several problems with our current approach to insulin sensitivity assessment in PCOS, including the apparent lack of consensus on what defines PCOS and "normal" insulin sensitivity, ethnic and genetic variability, the presence of other factors contributing to insulin resistance such as obesity, stress, and aging, and concern about whether simplified models of insulin sensitivity have the precision to predict treatment needs, responses, and future morbidity. Although the hyperinsulinemic-euglycemic clamp technique is the gold standard for measuring insulin sensitivity, it is too expensive, time-consuming, and labor-intensive to be of practical use in an office setting. Homeostatic measurements (fasting glucose/insulin ratio or homeostatic model assessment [HOMA] value) and minimal model tests (particularly the oral glucose tolerance test [OGTT]) represent the easiest office-based assessments of insulin resistance in the PCOS patient. The OGTT is probably the best simple, office-based method to assess women with PCOS because it provides information about both insulin resistance and glucose intolerance. The diagnosis of glucose intolerance holds greater prognostic and treatment implications. All obese women with PCOS should be screened for the presence of insulin resistance by looking for other stigmata of the insulin resistance syndrome such as hypertension, dyslipidemia, central obesity, and glucose intolerance.

Effect of rosiglitazone on insulin resistance, growth factors, and reproductive disturbances in women with polycystic ovary syndrome

OBJECTIVE

To evaluate the effects of rosiglitazone on insulin resistance, growth factors, and reproductive disturbances in women with polycystic ovary syndrome (PCOS).

DESIGN

Prospective study.

SETTING

Women with PCOS attending as outpatients of the Endocrine Division, Hospital Durand, Buenos Aires.

PATIENT(S)

Twenty-four insulin-resistant women with PCOS.

INTERVENTION(S)

Hormonal evaluations and a standardized oral glucose tolerance test before and after a 3-month trial of 4 mg of rosiglitazone daily.

MAIN OUTCOME MEASURE(S)

Serum LH, FSH, T, IGF-1, IGFBP-1, IGFBP-3, leptin, 17alpha-hydroxyprogesterone, insulin, and glucose concentrations. The area under insulin curve (AUC-insulin), the HOMA index (insulin resistance), the QUICKI index (insulin sensitivity), and the beta-cell function were calculated. Body mass index (BMI) and the waist/hip ratio were evaluated.

RESULT(S)

A significant decrease was observed in serum fasting insulin, AUC insulin, HOMA index, beta-cell function, IGF-1, LH, and waist/hip ratio. The QUICKI index and IGFBP-1 increased significantly. Serum sex hormone-binding globulin, androgens, leptin, IGFBP-3, and BMI remained unchanged. Twenty-two of 23 females had their menses restored, and three patients became pregnant. One patient was excluded because she became pregnant at the second month.

CONCLUSION(S)

Associated with the decrease in LH, rosiglitazone improved insulin-resistance parameters and normalized the menstrual cycle, which suggests that this drug could improve the endocrine-reproductive condition in insulin-resistant women with PCOS.

Pathogenesis of polycystic ovary syndrome: what is the role of obesity?

Both obesity and the polycystic ovary syndrome (PCOS) are commonly seen in women of reproductive age. Fifty percent of all patients with PCOS are obese, and the presence of obesity affects the clinical manifestations of PCOS. The underlying pathogenetic mechanisms appear to involve insulin resistance and hyperinsulinemia, the magnitude of which is greater in obese than in non-obese women with PCOS. Specific effects of obesity on the manifestations of PCOS, underlying mechanisms of the interactions between obesity and PCOS, and therapeutic implications of these interactions are discussed in this article.

Increased growth hormone response to clonidine in nonobese normoinsulinemic patients with polycystic ovary syndrome

OBJECTIVE

To assess growth hormone (GH) levels in response to acute clonidine stimulation in nonobese patients with polycystic ovary syndrome (PCOS) in comparison to patients with idiopathic hirsutism (IH) and normal women without hirsutism.

DESIGN

Cross-sectional study. Outpatient clinic, Porto Alegre, Brazil.

PATIENT(S)

Fourteen patients with PCOS, 11 women with IH, and 10 age- and weight-matched normal women without hirsutism were studied. All subjects presented normal body mass index (<25 kg/m(2)) and insulin levels (<25 microIU/mL).

INTERVENTION(S)

Growth hormone levels were assessed in all patients before and 30, 60, 90, and 120 minutes after oral administration of 0.3 mg of clonidine.

MAIN OUTCOME MEASURE(S)

Growth hormone levels before and after clonidine administration.

RESULT(S)

Delta GH and GH levels at 30, 60, and 120 minutes were significantly higher in the PCOS group than in the IH and control groups.

CONCLUSION(S)

The greater GH response to clonidine in nonobese normoinsulinemic PCOS patients observed in this study suggests a dysregulation in GH secretion in these patients. Further studies are required to elucidate the role of GH in the pathogenesis of PCOS and to investigate the existence of an association between androgens, IGF-I, and GH modulation in PCOS.

Serum leptin and body composition in polycystic ovarian syndrome

BACKGROUND

The role of leptin in polycystic ovarian syndrome (PCOS) is unclear. We investigated the relationship between serum leptin levels, body composition and insulin resistance in polycystic ovarian syndrome (PCOS).

METHODS

We analyzed differences between 27 patients with PCOS and 25 control subjects in serum glucose and leptin levels, insulin resistance, body fat mass, lean body mass, and water volume.

RESULTS

Serum leptin was significantly correlated with basal insulin levels, BMI and IR in both groups (P<0.01). Fat mass, fat percentage, lean mass and water volumes were positively correlated and lean percentage and water percentage were negatively correlated with leptin levels (P<0.05). Leptin levels were significantly different between the groups in a multivariate regression analysis after correcting for the difference in BMI and body fat percentage (P<0.05). When the effects of fat percentage on serum leptin were eliminated, the levels were significantly different between the PCOS and control groups, and were statistically more powerful than BMI (P<0.01).

CONCLUSION

These findings support the idea that factors other than excess fat mass or fat-free mass might be important in the regulation of serum leptin levels in PCOS.

Insulin-lowering agents in the management of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a medical condition that has brought multiple specialists together. Gynecologists, endocrinologists, cardiologists, pediatricians, and dermatologists are all concerned with PCOS patients and share research data and design clinical trials to learn more about the syndrome. Insulin resistance is a common feature of PCOS and is more marked in obese women, suggesting that PCOS and obesity have a synergistic effect on the magnitude of the insulin disorder. Hyperinsulinemia associated with insulin resistance has been causally linked to all features of the syndrome, such as hyperandrogenism, reproductive disorders, acne, hirsutism, and metabolic disturbances. Women with PCOS should be evaluated for cardiovascular risk factors, such as lipid profile and blood pressure. Modification of diet and lifestyle should be suggested to those who are obese. Several insulin-lowering agents have been tested in the management of PCOS. In particular, metformin is the only drug currently in widespread clinical use for treatment of PCOS. In a high percentage of patients, treatment with metformin is followed by regularization of menstrual cycle, reduction in hyperandrogenism and in cardiovascular risk factors, and improvement in response to therapies for induction of ovulation.

Metformin and gestational diabetes

Pregnancy increases requirements for insulin secretion, increasing insulin resistance and demands on pancreatic b cells, promoting development of gestational diabetes (GD), particularly in women with preexisting insulin resistance, commonly in women with polycystic ovary syndrome. Preliminary studies suggest that metformin may have the unique potential to prevent the development of GD. We postulate that interventions that reduce insulin resistance and lower requirements for endogenous insulin secretion can preserve b-cell function and prevent the development of type 2 diabetes mellitus.

Regulation of HOXA-10 expression by testosterone in vitro and in the endometrium of patients with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) affects approximately 5% of reproductive-age women and is characterized by anovulation and increased androgen production. Despite the ability to correct ovulatory disorders, pregnancy rates remain paradoxically low, and spontaneous pregnancy loss rates are high. To determine whether uterine dysfunction contributed to the adverse reproductive outcomes in PCOS, we assessed the effect of the increased ovarian androgens on a well-characterized gene essential to endometrial receptivity. Up-regulation of HOXA10 in the endometrium is necessary for receptivity to embryo implantation. In vitro, HOXA10 expression was repressed by testosterone but not by dehydroepiandrosterone, dehydroepiandrosterone sulfate, or insulin. Testosterone also prevented the increased expression of HOXA10 previously reported with estradiol or progesterone. Dihydrotestosterone produced an effect similar to that of testosterone, whereas flutamide blocked the testosterone effect. Endometrial biopsies, obtained from women with PCOS, demonstrated decreased HOXA10 mRNA. Testosterone is a novel regulator of HOXA10. Diminished uterine HOXA10 expression may contribute to the diminished reproduction potential of women with PCOS.

The contentious nature of gestational diabetes: diet, insulin, glyburide and metformin

Gestational diabetes (GD) develops because pregnancy increases requirements for insulin secretion while increasing insulin resistance. Women with GD often have impaired pancreatic beta-cell compensation for insulin resistance. The nature of GD is currently contentious, with debate about its existence, diagnosis and ramifications for both mother and offspring from pregnancy into later life. Also contentious are the outcomes of intervention with diet, insulin, glyburide (Glynase trade mark, Pharmacia Upjohn) and metformin (Glucophage trade mark, Bristol-Myers Squibb). There is consensus that women with unequivocal GD have a significant risk of adverse perinatal outcomes and increased risk of later type 2 diabetes mellitus. Foetuses from pregnancies with GD have a higher risk of macrosomia (associated with higher rate of birth injuries), asphyxia, and neonatal hypoglycaemia and hyperinsulinaemia. Uncontrolled GD predisposes foetuses to accelerated, excessive fat accumulation, insulin resistance, pancreatic exhaustion secondary to prenatal hyperglycaemia and possible higher risk of child and adult obesity and type 2 diabetes mellitus later in adult life. However, there is no consensus as to whether glucose intolerance of a severity below unequivocal GD is related to adverse maternal, fetal or perinatal outcomes, and whether this relationship is a continuous one. If dietary intervention is not sufficient in the treatment of GD, then, historically, insulin has been added. Recent studies suggest that glyburide may be efficaciously substituted for insulin. Preliminary studies suggest that metformin may have the unique potential to prevent the development of GD.

Treatment of polycystic ovary syndrome with insulin-lowering agents

Early diagnosis and therapy of the underlying insulin resistance of heritable polycystic ovary syndrome (PCOS), often manifested at menarche, facilitate the reduction and/or reversal of the reproductive and metabolic morbidity of PCOS, as well as reduce the risk factors for cardiovascular disease. PCOS is characterised by oligoamenorrhoea, clinical and biochemical hyperandrogenism, infertility, recurrent miscarriage, insulin resistance, hyperinsulinaemia, gestational diabetes, impaired glucose tolerance, Type 2 diabetes, morbid obesity, hypertension, hypofibrinolysis, hypertriglyceridaemia, low levels of high density lipoprotein-cholesterol and a sevenfold risk increase in cardiovascular disease. Insulin sensitising-lowering agents reduce insulin resistance and hyperinsulinaemia, reverse PCOS endocrinopathy and ameliorate the reproductive, metabolic and cardiovascular morbidity of the disorder. The largest literature on the subject discusses metformin. Improved pregnancy outcomes in women with PCOS receiving metformin may be attributed to its ability to reduce insulin resistance, hyperinsulinaemia and hypofibrinolytic plasminogen activator inhibitor activity by the enhancement of folliculogenesis and improvement of oocyte quality.

Metformin therapy in the management of polycystic ovary syndrome: endocrine, metabolic and reproductive effects

Polycystic ovary syndrome (PCOS) is a convergence of multisystem endocrine derangements. Impairment in insulin metabolism is a prominent feature of the syndrome and appears to play a key pathogenetic role precipitating the cascade of other disorders associated with PCOS. Recent studies report that insulin-sensitizing agents, such as metformin, reduce hyperinsulinemia, reverse the endocrinopathy of PCOS and normalize endocrine, metabolic and reproductive functions, leading to the resumption of menstrual cyclicity and ovulation. In this review, we report the most recent evidence regarding metformin usage in women with PCOS.