Hormonal responses to physical exercise in patients with polycystic ovarian syndrome**Supported by grants from the Emil Aaltonen Foundation, Tampere, Finnish Gynecological Association, Helsinki, and the Paulo Foundation, Helsinki, Finland

Exploring factors related to changes in body composition, insulin sensitivity and aerobic capacity in response to a 12-week exercise intervention in overweight and obese women with and without polycystic ovary syndrome

Objective

To determine factors associated with differential changes in body fat, insulin resistance and aerobic capacity following a 12-week exercise intervention in overweight and obese women with and without polycystic ovary syndrome (PCOS).

Methods

16 overweight and obese women (9 PCOS; 7 without PCOS) completed a supervised progressive 12-week exercise program. Primary outcomes included changes in indicators of insulin sensitivity (including glucose infusion rate relative to fat-free mass [GIR/FFM]), body composition, and aerobic capacity (VO₂ peak; 12 participants only). Comparisons were made between women with and without PCOS, and between participants who lost ≥5% (classified as exercise responders) and <5% (non-responders) in body fat (assessed by dual-energy X-ray absorptiometry).

Results

Training decreased body fat percentage by (mean; 95% CI) -2.3%; -5.3, 0.7% in women with PCOS and by -6.4%; -10.9, -1.9% in women without PCOS (P = 0.08). Ten women (7 PCOS; 3 without PCOS) did not reduce body fat by ≥5%. All participants improved VO₂ peak (mean change 27%; 16–39%) but four (2 PCOS; 2 without PCOS) demonstrated decreases in GIR/FFM (mean change for whole cohort: 37%; 3–71%). Android-gynoid fat ratio (0.58; 0.51, 0.66 vs 0.46; 0.40, 0.51; P<0.01) was significantly higher and GIR/FFM (6.69; 3.49, 9.90 vs 11.44; 9.15, 13.72 mg/kg/min; P = 0.01) was significantly lower in non-responders compared with responders at baseline, but non-responders had significant post-training decreases in android-gynoid ratio (-0.02; -0.04, -0.01; P = 0.03), and increases in VO₂ peak (7.24; 2.28, 12.21 mL/kg/min; P = 0.01) and GIR/FFM (1.44; 0.27, 2.61 mg/kg/min; P = 0.02). In women with PCOS, pre-training VO₂ peak was significantly negatively correlated with change in total body fat (r = -0.75; P = 0.02), and pre-training fasting glucose negatively correlated with changes in VO₂ peak (r = -0.76; P = 0.04), but positively correlated with changes in GIR (r = 0.67; P = 0.046).

Conclusion

A high proportion of overweight and obese women with PCOS had small reductions in body fat following a 12-week exercise intervention, but nevertheless significantly reduced relative central adiposity and improved aerobic capacity and insulin sensitivity.

Administration of exogenous ghrelin in obese patients with polycystic ovary syndrome: effects on plasma levels of growth hormone, glucose, and insulin

OBJECTIVE

To assess the effects of the administration of exogenous ghrelin, a peptide with potent GH-releasing activity and glucose-enhancing and insulin-lowering properties, in obese patients with polycystic ovary syndrome (PCOS).

DESIGN

Prospective, controlled study.

SETTING

Academic research environment.

PATIENT(S)

Twenty obese women with PCOS, and 15 obese controls.

INTERVENTION(S)

Oral glucose tolerance test (OGTT) and ghrelin test (1 microg/kg i.v. bolus).

MAIN OUTCOME MEASURE(S)

Basal hormonal assays, including ghrelin, were performed. Glucose, insulin, and C-peptide were assessed in a fasting condition and during the OGTT. Growth hormone, insulin, and glucose were measured basally and every 15 minutes for 90 minutes after the injection of ghrelin.

RESULT(S)

Both groups showed an insulin response to the glucose load above the normal range. Significantly lower levels of ghrelin were detected in patients with PCOS compared to controls (108.96 +/- 27.65 Fmol/mL versus 162.47 +/- 42.23 Fmol/mL). Administration of ghrelin markedly enhanced GH levels in both groups (1,888.59 +/- 1,209.53 ng/mL and 1,639.95 +/- 631.79 ng/mL per 90 minutes as GH area under the curve, respectively), with a peak occurring 30 minutes after injection. Ghrelin also induced a trend toward an increase in plasma glucose levels, and a significant decrease in insulin concentrations in both groups.

CONCLUSION(S)

The injection of ghrelin seems to override the GH secretion defect in obese women with PCOS, and to induce glucoinsulinemic changes in both controls and obese patients with PCOS.

Review article: The impact of obesity on reproduction in women with polycystic ovary syndrome

The polycystic ovary syndrome (PCOS) is one of the most common causes of infertility due to anovulation in women. The clinical features of PCOS are heterogeneous and may change throughout the lifespan, starting from adolescence to postmenopausal age. This is largely dependent on the influence of obesity and metabolic alterations, including an insulin-resistant state and the metabolic syndrome, which consistently affect most women with PCOS. Obesity does in fact have profound effects on both the pathophysiology and the clinical manifestation of PCOS, by different mechanisms leading to androgen excess and increased free androgen availability and to alterations of granulosa cell function and follicle development. Notably, simple obesity per se represents a functional hyperandrogenic state. These mechanisms involve early hormonal and metabolic factors during intrauterine life, leptin, insulin and the insulin growth factor system and, potentially, the endocannabinoid system. Compared with normal weight women with PCOS, those with obesity are characterised by a worsened hyperandrogenic and metabolic state, poorer menses and ovulatory performance and, ultimately, poorer pregnancy rates. The importance of obesity in the pathogenesis of PCOS is emphasised by the efficacy of lifestyle intervention and weight loss, not only on metabolic alterations but also on hyperandrogenism, ovulation and fertility. The increasing prevalence of obesity among adolescent and young women with PCOS may partly depend on the increasing worldwide epidemic of obesity, although this hypothesis should be supported by long-term prospective epidemiological trials. This may have great relevance in preventive medicine and offer the opportunity to expand our still limited knowledge of the genetic and environmental background favouring the development of the PCOS.

Role of changes in dietary habits in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a heterogeneous clinical condition. In most women, especially in the obese, all features of the metabolic syndrome, particularly insulin resistance and associated hyperinsulinaemia, are present. Insulin is a physiological hormone regulating ovarian function, specifically ovarian steroidogenesis and androgen blood transport and/or activity in the target tissues. Hyperinsulinaemia may therefore play a pivotal role in favouring the hyperandrogenic state and related clinical and metabolic alterations. The abdominal obesity phenotype is common, affecting more than half of PCOS women. Menstrual cycles and fertility rate are negatively affected by the presence of insulin resistance, hyperinsulinaemia and obesity. PCOS women with obesity and insulin resistance are the obvious target for lifestyle intervention, such as changes in dietary habits and increased physical activity. Weight loss should therefore represent the first-line approach in the treatment of obese PCOS women, since it significantly improves hormonal and metabolic abnormalities and may favour spontaneous ovulation and improve fertility rate in the majority of patients. Individualized pharmacological support aimed at favouring weight loss and maintenance and improving insulin resistance may play a complementary role to lifestyle intervention.

Polycystic ovary syndrome and fat distribution: the central issue?

This review discusses the role of central obesity in polycystic ovary syndrome. There is increasing evidence that intraabdominal or visceral fat is either causative or a very early effect of polycystic ovary syndrome. The clinical implications of this are discussed. The simplest technique for assessing visceral fat and monitoring treatment is to measure waist circumference rather than waist:hip ratio or body weight. Weight loss is an effective treatment even where there is only a very modest reduction. The key element in lifestyle modification is regular exercise.

Polycystic ovary syndrome: current and future treatment paradigms

Polycystic ovary syndrome is characterized by excess levels of circulating androgens and by chronic anovulation. Although the fundamental pathophysiologic defect has not been determined, women with polycystic ovary syndrome are known to be uniquely insulin resistant. Obesity in polycystic ovary syndrome aggravates the underlying predisposition towards insulin resistance. Diagnostic criteria that focus on menstrual irregularity are more likely to discriminate insulin-resistant women than are such criteria as abnormal gonadotropin secretion or ovarian morphologic characteristics. About 40% of patients with polycystic ovary syndrome demonstrate glucose intolerance (either impaired glucose tolerance or type 2 diabetes) in response to an oral glucose challenge. The lack of a clear causal mechanism in the syndrome has led to a multitude of symptom-oriented treatments, with few therapies improving all aspects of the endocrine abnormalities associated with polycystic ovary syndrome. Many of these therapies-such as ovulation induction with medical agents-hold increased risks for women with polycystic ovary syndrome, including ovarian hyperstimulation syndrome and multiple gestation. Empirical studies of interventions that improve insulin sensitivity in polycystic ovary syndrome (either weight loss and diet programs or pharmaceutical agents) have been shown to improve the endocrine abnormalities in the syndrome. Initial results with antidiabetic agents (specifically insulin-sensitizing agents) are promising but need to be confirmed with larger, randomized studies.

Insulin resistance in polycystic ovary syndrome: treating a phenotype without a genotype

PCOS women are uniquely insulin resistant. The underlying genetic defect in insulin action is unknown. Obesity aggravates the underlying predisposition to insulin resistance. Diagnostic criteria which focus on menstrual irregularity are more likely to identify insulin resistant women. About 40% of PCOS women display glucose intolerance (either impaired glucose tolerance or type 2 diabetes) in response to an oral glucose challenge. The lack of a clear etiologic mechanism to the syndrome has led to a multitude of symptom-oriented treatments with few therapies improving all aspects of the endocrine syndrome of PCOS. Empirical studies of interventions improving insulin sensitivity in PCOS, either weight loss/diet programs or pharmaceutical agents, have been shown to improve the endocrine abnormalities in the syndrome. These initial results with anti-diabetic agents, though promising, need to be confirmed in larger, randomized studies.

Serum free testosterone in polycystic ovary syndrome measured with a new reference method

OBJECTIVE

To quantify the actual serum free T with a specific new reference method in women with polycystic ovary syndrome (PCOS) and to analyze the effects of serum free T, total T, and the T:sex hormone-binding globulin (SHBG) ratio on the diagnosis of PCOS.

SETTING

Outpatient clinic of reproductive endocrinology at Turku University Central Hospital, Turku, Finland.

PATIENTS

Forty-four oligomenorrheic women with PCOS and 26 weight-matched control women with regular menstrual cycles.

MAIN OUTCOME MEASURES

The concentrations of free T, total T, androstenedione (A), LH, FSH, SHBG, and insulin in serum.

RESULTS

The mean concentrations of free T, total T, A, and LH as well as the LH:FSH and T:SHBG ratios were higher, whereas the mean concentrations of FSH was lower in the women with PCOS than in healthy women. No differences were found in the free T, total T, or T:SHBG levels or in the body mass indexes (BMIs) between the hirsute (n=26) and nonhirsute (n = 18) women with PCOS. Both elevated free T concentrations and high T:SHBG ratios were associated with obesity, but serum total T was independent of BMI. The serum free T measurement discriminated PCOS women from controls to a similar extent as total T and T:SHBG ratio as judged by a receiver operating characteristics analysis.

CONCLUSIONS

The present data indicate that determination of free T provides little additional information in the diagnosis of hirsutism or PCOS and does not have to be included to the basic evaluation of these patients. Only half of women with PCOS exhibited elevated serum free T concentrations.