Why does ovarian surgery in PCOS help? Insight into the endocrine implications of ovarian surgery for ovulation induction in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a complex disorder with heterogeneity of clinical and endocrine features. Ovarian surgery for ovulation induction has been used in the management of clomiphene citrate-resistant anovulatory women with PCOS. Various types of ovarian surgery have been employed (wedge resection, electrocautery, laser vaporization, multiple ovarian biopsies and others) and all procedures result in an altered endocrine profile after surgery. The mechanism behind the reversal of endocrinological dysfunction in PCOS after ovarian surgery remains incompletely understood. This review scans the literature systematically to identify the endocrine changes after ovarian surgery in PCOS, in order to glean some knowledge of the mechanism involved. After ovarian surgery in PCOS, a rapid reduction in serum levels of all ovarian hormones is seen, in combination with increased serum levels of pituitary hormones. Folliculogenesis is then initiated and ovarian hormone production increases, synchronically with a reduction of pituitary hormones. Continuation of follicle growth in subsequent cycles after ovarian surgery occurs in an environment with less androgens and lower LH and FSH levels compared with pretreatment levels. The endocrine changes found after ovarian surgery in PCOS women seem to be governed by the ovaries themselves. Rapid reduced secretion of all ovarian hormones restores feedback to the hypothalamus and pituitary, resulting in appropriate gonadotrophin secretion. Initiation of follicular development seems to be induced by increasing FSH levels following a reduction of the follicle excess and (intra-ovarian) androgen levels. Additionally, anti-Müllerian hormone and gonadotrophin surge attenuating factor probably have a role in the endocrine changes.

Use of fasting blood to assess the prevalence of insulin resistance in women with polycystic ovary syndrome

OBJECTIVE

To determine the prevalence of insulin resistance (IR) in women with polycystic ovary syndrome (PCOS) using baseline fasting blood measurements of glucose and insulin.

DESIGN

Prospective clinical study.

SETTING

Academic endocrinology unit in Palermo, Italy.

PATIENT(S)

Two hundred and sixty-seven women with PCOS, consecutively evaluated, and 50 consecutively selected ovulating controls.

INTERVENTION(S)

Fasting blood was obtained for glucose and insulin measurements from all women. For 60 women with PCOS and 20 controls an insulin tolerance test (ITT) was also performed.

MAIN OUTCOME MEASURE(S)

Assessment of normal and abnormal values for fasting insulin, glucose/insulin ratio, and the calculated indices of the homeostasis model assessment (HOMA), quantitative sensitivity check index (QUICKI), as well as Kitt (kinetic disappearance of glucose) values after ITT. Evaluation was performed of the ability to detect IR using these methods in obese and nonobese women with PCOS.

RESULT(S)

Normal insulin sensitivity was defined by insulin levels <12 mU/mL, glucose/insulin ratios of >6.4, HOMA values of <47, and QUICKI values of >0.333. In the entire PCOS groups, IR was diagnosed in 65.4% of women using glucose/insulin ratios and in 77% and 79.2% using HOMA and QUICKI. In obese women (body mass index >28 in 48% of group), IR was present in 76.7% as measured by glucose/insulin ratios but was significantly higher (95.3%) using values of either HOMA or QUICKI (P<.01). All indices correlated with Kitt values with QUICKI showing the best correlation.

CONCLUSION(S)

Insulin resistance was detected in approximately 80% of women with PCOS, and in 95% of obese women. The detection of IR is superior using the calculated indices HOMA and QUICKI.

IGF1 genotype, mean plasma level and breast cancer risk in the Hawaii/Los Angeles multiethnic cohort

The insulin-like growth factor 1 gene (IGF1) is a strong candidate gene for a breast cancer susceptibility model. We investigated a dinucleotide repeat 969 bp upstream from the transcription start site of the IGF1 gene for possible associations with plasma IGF1 levels and breast cancer risk in a multiethnic group of postmenopausal women. Furthermore, we investigated the relation between race/ethnicity, mean plasma IGF1 levels and breast cancer rates in the Hawaii/Los Angeles Multiethnic Cohort. The mean age-adjusted IGF1 level among Latino-American women, 116 ng ml(-1), was statistically significantly lower than the mean age-adjusted IGF1 levels for each of the three other racial/ethnic groups, African-American, Japanese-American and Non-Latino White women (146, 144 and 145 ng ml(-1), respectively) (P<0.0001). Latino-American women have the lowest breast cancer rates of any racial/ethnic group in the cohort. These results support the investigation of an expansion of the hypothesis for an important role of IGF1 in breast cancer tumorigenesis to different racial/ethnic groups and to postmenopausal women. It is unlikely that any involvement of IGF1 in breast cancer aetiology is mediated by the IGF1 dinucleotide repeat polymorphism, which was not significantly associated with circulating IGF1 levels nor breast cancer risk in this study. Research into relevant determinants of IGF1 levels in the blood must continue.

Circulating leptin levels during ovulation induction: relation to adiposity and ovarian morphology

OBJECTIVE

To assess serum leptin levels based on body habitus and ovarian morphology during controlled ovarian hyperstimulation.

DESIGN

Prospective analysis.

SETTING

University IVF program.

PATIENT(S)

Women undergoing IVF-ET were divided into two groups, obese ovulatory women (n = 6; mean (+/-SD) body mass index, 30.1 +/- 0.6 kg/m(2)) and lean ovulatory women (n = 20); mean (+/- SD) body mass index 22.0 +/- 0.2 kg/m(2)). Lean women were categorized further according to whether they had polycystic-appearing ovaries (n = 8) or normal-appearing ovaries (n = 12).

INTERVENTION(S)

Controlled ovarian hyperstimulation and IVF.

MAIN OUTCOME MEASURE(S)

Serum estradiol, testosterone, and leptin.

RESULT(S)

Mean (+/- SD) leptin levels were significantly higher before and after GnRH agonist down-regulation in obese women (41.7 +/- 5.2 pg/mL and 36.1 +/- 5.8 pg/mL, respectively) compared with lean women (8.4 +/- 1.0 pg/mL and 6.9 +/- 1.1 pg/mL, respectively). Mean (+/- SD) leptin levels increased significantly in both groups (54.5 +/- 5.1 pg/mL and 11.7 +/- 1.2 pg/mL, respectively), and the mean (+/-SD) percentage increase was similar (55% +/- 18% and 54.8% +/- 17%, respectively). Mean (+/-SD) leptin levels were similar in women with polycystic-appearing and normal-appearing ovaries before controlled ovarian hyperstimulation, but increased significantly in women with polycystic-appearing ovaries afterward (14.7 +/- 1.8 pg/mL and 9.3 +/- 1.0 pg/mL, respectively).

CONCLUSION(S)

Significant increases in leptin levels occur during controlled ovarian hyperstimulation, suggesting that leptin plays a role in follicular growth and maturation. The exaggerated response in women with polycystic-appearing ovaries reflects either a greater number of recruited follicles or a predisposition of adipocytes to leptin production.

Evidence that insulin and androgens may participate in the regulation of serum leptin levels in women

OBJECTIVE

Although serum leptin is principally influenced by body mass, to understand the role of insulin and androgens in the regulation of serum leptin in normal weight women.

DESIGN

Prospective observational study.

SETTING

Academic practice in reproductive endocrinology.

PATIENT(S)

Twenty-one women with polycystic ovary syndrome (PCOS) of normal body weight, 8 apparently normal women with polycystic-appearing ovaries (PAO), and 21 normal women.

INTERVENTION(S)

Fasting blood levels of luteinizing hormone, follicle-stimulating hormone, testosterone (T), unbound T, dehydroepiandrosterone sulfate (DHEAS), insulin, insulin growth factor-binding protein-1 (IGFBP-1), and leptin.

MAIN OUTCOME MEASURE(S)

Comparisons of measured hormones in the different groups and correlative analysis

RESULT(S)

Women with PCOS had higher levels of serum luteinizing hormone, T, unbound T, DHEAS and insulin, and lower levels of IGFBP-1 compared with the normal controls, but they had similar leptin levels. Normal women with PAO had increased levels of insulin and leptin compared with controls, whereas IGFBP-1 was lower in PAO. In normal weight women with PCOS and PAO, leptin correlated positively with body weight and insulin, and negatively with IGFBP-1 and DHEAS.

CONCLUSION(S)

In normal weight patients serum leptin levels may be regulated in part by insulin. Androgens, on the other hand, may play a role in suppressing serum leptin.

The contributions of oestrogen and growth factors to increased adrenal androgen secretion in polycystic ovary syndrome

Adrenal hyperandrogenism is prevalent in many women with polycystic ovary syndrome (PCOS), although the expression of this enhanced secretion may be heterogeneous. Since no single factor acts in isolation, this study was performed to assess the influence of oestradiol (total and unbound), insulin, insulin-like growth factor (IGF)-I, IGF-II and the binding proteins IGFBP-I, and IGFBP-3, on basal and adrenocorticotrophic hormone (ACTH) stimulated adrenal androgen secretion in 25 women with PCOS and 10 matched ovulatory controls. Women with PCOS exhibited elevations of all androgens as well as unbound oestradiol, insulin and non-IGFBP-1 bound IGF-I. Positive correlations were noted between oestrogen and basal and ACTH stimulated delta 5 adrenal androgens. Serum IGF-I was only correlated with basal dehydroepiandrosterone sulphate (DHEA-S), while insulin exhibited a strong correlation with the delta 4 pathway and androstenedione formation in particular. This correlation was also confirmed by dividing the PCOS group into those women with and without hyperinsulinaemia. The activity of 17,20 lyase favouring androstenedione was increased in the hyperinsulinaemic women. By multivariate analyses, body mass index did not influence these findings. Although there are inherent difficulties in making major conclusions based on correlative analyses, it is suggested that oestrogen may have a greater influence on enhancing delta 5 adrenal androgen secretion, and insulin a greater effect on the delta 4 pathway. In turn, the relative importance of these influences may contribute to the heterogeneous nature of adrenal hyperandrogenism in PCOS.