Role of insulin in the hyperandrogenemia of lean women with polycystic ovary syndrome and normal insulin sensitivity

Hyperinsulinemia is closely related to low urinary clearance of D-chiro-inositol in men with a wide range of insulin sensitivity

We have previously shown that women with polycystic ovary syndrome (PCOS) have increased urinary clearance of D-chiro-inositol (uCl(DCI)), which was positively associated with hyperinsulinemia. The objective of this study was thus to determine if such relationship also exists in men with a large range of insulin sensitivity and levels. A cross-sectional study was performed on 11 brothers of women with PCOS and 21 control men. In this study, brothers served as a model of insulin resistance. We assessed uCl(DCI), urinary clearance of myo-inositol, and insulin levels with a standard 75-g oral glucose tolerance test, a 2-hour euglycemic-hyperinsulinemic clamp, and a 24-hour urine collection. Our results showed in all men together that low uCl(DCI) was strongly associated (P < .001) with hyperinsulinemia, for which uCl(DCI) was a significant predictor independent of other classic factors. Brothers were heavier than controls (P = .02), with increased glucose-stimulated glucose (P < .001) and insulin levels (P < .001) and reduced insulin sensitivity (P = .001). In this group, plasma DCI was increased by 3-fold (P = .02), with a 3-fold decrease in the uCl(DCI) to urinary clearance of myo-inositol ratio, which was almost significant (P = .07). Low uCl(DCI) is strongly associated with hyperinsulinemia in all men, and brothers of PCOS women who are more insulin resistant display increased plasma DCI and borderline decreased uCl(DCI). Thus, compensatory hyperinsulinemia might suppress renal clearance of DCI to increase plasma DCI levels and partially compensate for insulin resistance by improving DCI availability in men. The apparent discrepancy with PCOS women might be explained by higher insulin levels in men as compared with women and requires confirmation.

Polymorphism T --> C (-34 base pairs) of gene CYP17 promoter in women with polycystic ovary syndrome is associated with increased body weight and insulin resistance: a preliminary study

The aim of this study was to establish the frequency of gene CYP17 promoter polymorphism in women with polycystic ovary syndrome (PCOS) from a Chilean population and to examine the association of this polymorphism with body weight and estimate of insulin resistance in PCOS patient carriers and noncarriers of the A2 allelic variant. A total of 159 women with clinical and hormonal evidence of PCOS and 93 healthy women (HW) were evaluated. Diagnosis of PCOS was made according to the National Institutes of Health consensus criteria. In PCOS and HW, an oral glucose tolerance test was performed; and serum glucose and insulin were measured before the glucose load and 30, 60, 90, and 120 minutes after. Lipid profile and free fatty acid concentrations were determined in the basal sample. Insulin resistance was evaluated by homeostatic model assessment and insulin sensitivity index composite. A polymerase chain reaction-restriction fragment length polymorphism analysis was performed in all women to determine the A2 allele of the gene CYP17 promoter. The genotype frequency was similar between HW and PCOS women. No differences in anthropometric measurements and metabolic parameters were observed in HW carrier and noncarrier of the A2 variant. In PCOS women, an increase in body mass index, waist circumference, homeostatic model assessment of insulin resistance, and fasting insulin according to the A2 allele dosage was observed (P = .008, P = .016, P = .012, and P = .006, respectively). Polycystic ovary syndrome patient carriers of the A2 allele with a body mass index greater than 29.9 kg/m(2) showed an odds ratio of 9.1 (confidence interval, 3.0-27.4; P < .0001) for developing insulin resistance. These data suggest that the frequency of the A2 allele is similar between PCOS patients and HW; however, the presence of this gene defect in PCOS patients seems to be associated with increase in body weight, abdominal adiposity, and metabolic components.

Differential effects of insulin sensitivity on androgens in obese women with polycystic ovary syndrome or normal ovulation

The differential effects of insulin sensitivity and adiposity on androgen concentrations in women with polycystic ovary syndrome (PCOS) are unclear. To address this issue, we divided 43 overweight women into 4 groups based on both their clinical classification (PCOS or normal) and whether they were insulin resistant (IR) or insulin sensitive (IS) by their steady-state plasma glucose concentrations. Total testosterone concentrations were significantly increased as a function of both clinical classification (PCOS vs normal, P < .0001) and steady-state plasma glucose concentration (IR vs IS, P = .002). Mean testosterone concentrations were higher in PCOS-IR compared with PCOS-IS, normal-IR, or normal-IS women (P < .005). In addition, there was a statistically significant interaction (P = .03) between clinical classification (PCOS vs normal) and insulin sensitivity (IR vs IS) for testosterone concentrations. In contrast, androstenedione concentrations were higher in women with PCOS (P = .001), irrespective of whether they were IR or IS (P = .31); and no interaction between clinical classification and insulin sensitivity was discerned (P = .34). These results indicate that both PCOS and insulin resistance independently contributed to increased total testosterone concentrations within a group of overweight/obese women. These findings are consistent with the hypothesis that the ovaries of women with PCOS are hypersensitive to the ability of insulin to increase testosterone production and that the more insulin resistant the patient, the higher the testosterone concentration. In contrast, androstenedione concentrations seem to be independent of differences in insulin resistance. Our findings emphasize the need to increase understanding of the factors that modulate ovarian androgen secretion.

Basic infertility including polycystic ovary syndrome

Infertility in women has many possible causes and must be approached systematically. The most common cause of medically treatable infertility is the polycystic ovary syndrome (PCOS). This syndrome is common in young women and is the cause of anovulatory infertility in 70% of cases. It is therefore an important condition to screen and manage in primary care medical settings. In the past 10 years, insulin sensitization with weight loss or metformin has been shown to be a safe and effective treatment for PCOS infertility that eliminates the risk of multiple pregnancy and may reduce the risk of early pregnancy loss as compared with ovulation-inductor drugs. The authors believe metformin should be considered as first-line therapy because it has the advantage to allow for normal single ovulation, for reduced early pregnancy loss, and, most importantly, lifestyle modifications and weight loss before pregnancy. Losing weight not only improves fertility but also reduces adverse pregnancy outcomes associated with obesity.

Greek hyperinsulinemic women, with or without polycystic ovary syndrome, display altered inositols metabolism

BACKGROUND We have shown that American women with polycystic ovary syndrome (PCOS) have decreased glucose-stimulated release of a putative mediator of insulin action, D-chiro-inositol (DCI)-containing inositolphosphoglycan (DCI-IPG), and increased urinary clearance of DCI (uCl(DCI)), which was associated with hyperinsulinemia.

METHODS

DCI levels and the release of insulin and DCI-IPG during an oral glucose tolerance test (AUCs) were assessed in 27 Greek PCOS and 10 normal Greek women.

RESULTS

PCOS women were heavier than controls (BMI = 28.4 versus 23.7 kg/m(2), P = 0.05) with higher waist-to-hip ratios (WHR = 0.78 versus 0.71, P = 0.009) and increased free testosterone (P = 0.048) and AUC(insulin) (P = 0.04). In PCOS women, incremental AUC(DCI-IPG) was significantly decreased by 59% (2158 versus 5276%.min, P = 0.01), even after correction for BMI and WHR. Finally, increased uCl(DCI) (r = 0.35, P = 0.04) and decreased AUC(DCI-IPG) (r = 0.46, P = 0.004) were significantly associated with hyperinsulinemia in all women together, even after correction for BMI and WHR (Ps = 0.02 and 0.007), and regardless of PCOS status.

CONCLUSIONS

Greek women, with or without PCOS, display increased uCl(DCI) and decreased AUC(DCI-IPG) in association with higher insulin levels but independent of adiposity. Increased clearance of inositols might reduce tissue availability of DCI and decrease the release of DCI-IPG mediator, which could contribute to insulin resistance and compensatory hyperinsulinemia in Greek women, as previously described in American women.

Polycystic ovarian syndrome: pathophysiology, molecular aspects and clinical implications

Polycystic ovarian syndrome (PCOS) is universally recognised as the commonest endocrinopathy of women. The definition and the aetiological hypotheses of PCOS are continuously evolving to accommodate expanding knowledge on the syndrome, which is now known to be more complex than purely a reproductive disorder. Increased androgen synthesis, disrupted folliculogenesis and insulin resistance lie at the pathophysiological core of PCOS. An intriguing concept involves the perpetuation of a vicious circle with endocrine/reproductive and metabolic components. An unfavourable metabolic environment may unmask genetic traits of ovarian dysfunction, and the unfolding endocrine derangement could further aggravate the metabolic disarray. This article reviews the molecular mechanisms known to underlie the ovarian and metabolic abnormalities characterising PCOS. The putative interdependence between reproductive and metabolic aspects of PCOS, and therapeutic implications for the management of PCOS, are also discussed.

Menstrual health and the metabolic syndrome in adolescents

The metabolic syndrome, a constellation of interrelated risk factors for cardiovascular disease and type 2 diabetes mellitus, has become a major public health concern against the backdrop of increasing rates of obesity. Insulin resistance plays a pivotal role as the underlying pathophysiological linchpin of the various components of the syndrome. The metabolic syndrome is well recognized in adults, and there is convincing evidence that it starts in childhood, with progressive clustering of the various components over time and tracking through adulthood. Adult women and adolescents with polycystic ovary syndrome (PCOS) have higher prevalence rates of the metabolic syndrome compared with the general population. Several anthropometric (obesity, particularly abdominal obesity), metabolic (insulin resistance/hyperinsulinemia, dyslipidemia) and hormonal (low IGFBP1, IGFBP2 and low sex hormone binding globulin) features of adolescents with PCOS are also features of the metabolic syndrome. Insulin resistance, believed to be a key pathogenic factor in both PCOS and the metabolic syndrome, may be the thread that links the two conditions. Menstrual health in adolescents could be viewed as yet another component in the evaluation of the metabolic syndrome. Careful assessment of menstrual history and appropriate laboratory work-up could reveal the presence of PCOS in obese at-risk adolescent girls with a family history of the metabolic syndrome.

Adrenocortical dysregulation as a major player in insulin resistance and onset of obesity

The aim of this review is to explore the dysregulation of adrenocortical secretions as a major contributor in the development of obesity and insulin resistance. Disturbance of adipose tissue physiology is one of the primary events in the development of pathologies associated with the metabolic syndrome, such as obesity and type 2 diabetes. Several studies indicate that alterations in metabolism of glucocorticoids (GC) and androgens, as well as aldosterone in excess, are involved in the emergence of metabolic syndrome. Cross talk among adipose tissue, the hypothalamo-pituitary complex, and adrenal gland activity plays a major role in the control of food intake, glucose metabolism, lipid storage, and energy balance. Perturbation of this cross talk induces alterations in the regulatory mechanisms of adrenocortical steroid synthesis, secretion, degradation, and/or recycling, at the level of the zonae glomerulosa (aldosterone), fasciculata (GC and GC metabolites), and reticularis (androgens and androgen precursors DHEA and DHEAS). As a whole, these adrenocortical perturbations contribute to the development of metabolic syndrome at both the paracrine and systemic level by favoring the physiological dysregulation of organs responsive to aldosterone, GC, and/or androgens, including adipose tissue.