Potential Utility of Insulin Sensitizers in the Treatment of Patients with Polycystic Ovary Syndrome

Insulin Sensitizers Modulate GnRH Receptor Expression in PCOS Rats

BACKGROUND

Insulin sensitizers like metformin and pioglitazone are clinically used since last decades for the treatment of PCOS, but their efficacy and possible role in PCOS patients remains questionable. Also, the mechanism by which these insulin sensitizers show effect is not clear.

AIM OF THE STUDY

To evaluate the effect of metformin and pioglitazone on leutinizing hormone and follicle stimulating hormone receptor mRNA expression, hyperandrogenism and insulin resistance in high fat diet induced and letrozole induced PCOS in rats.

METHODS

Pre-pubertal female rats were divided into four groups: group I received normal pellet diet and group II, III and IV received high fat diet. After 105 d of dietary manipulation, metformin and pioglitazone treatment was given to group III and group IV animals respectively for 21 d. Similarly, adult female rats were divided into four groups: group I received 1% carboxymethyl cellulose (CMC) and group II, III, IV received letrozole for 21 d. After 21 d of letrozole administration, metformin and pioglitazone treatment was given to group III and group IV animals respectively for 21 d. Oral glucose tolerance test, lipid profile, fasting glucose, insulin, estrus cycle, hormonal profile, ovary weight, leutinizing hormone receptor and follicle stimulating hormone receptor mRNA expression was measured. Polycystic ovarian morphology was assessed through histopathological changes of ovary.

RESULTS AND CONCLUSION

Metformin and pioglitazone treatment improve both metabolic and reproductive parameters of PCOS including hyperinsulinemia and hyperandrogenism. LH receptor and FSH receptor mRNA expression were altered by pioglitazone and metformin treatment.

Role of osteocalcin, tumor necrosis factor-alpha and adiponectin in polycystic ovary syndrome patients with insulin resistance

Objective:

Insulin resistance (IR) seems to be the main pathogenic factor in polycystic ovary syndrome (PCOS). Adiponectin and tumor necrosis factor-alpha (TNF-α) are important in IR. The aim of this study was to evaluate the correlations of osteocalcin, adiponectin, and TNF-α with IR in PCOS.

Materials and Methods:

A total of 60 women were divided into two groups. The first group constituted 44 patients with PCOS and the control group comprised 16 healthy women. Osteocalcin, adiponectin, TNF-α levels, body mass index (BMI), and IR in the fasting state were assessed and correlations of these parameters were evaluated.

Results:

Homeostasis model assessment (HOMA)-IR, adiponectin, osteocalcin, and androstenedione levels were significantly increased in the PCOS group. A moderate positive correlation between BMI and HOMA-IR, a moderate negative correlation between TNF-α and osteocalcin, and a mild negative correlation between adiponectin and BMI were detected in PCOS.

Conclusion:

Osteocalcin may have impact on adiponectin, TNF-α, and IR levels in PCOS. Different osteocalcin levels in patients with PCOS may be responsible for explaining PCOS heterogeneity.

Use of Follicle-Stimulating Hormone for the Treatment of Female Infertility – Current Concepts

Ovulatory dysfunction, which is common among women of reproductive age, often results in infertility. Over the last three decades, follicle-stimulating hormone (FSH), in the form of either urinary human menopausal gonadotropin or highly purified urinary FSH (uFSH), has been the mainstay in the treatment of women with ovulatory dysfunction. However, these preparations have several disadvantages, including variable composition, contamination with urinary proteins, and the limited availability of human menopausal urine from which uFSH is extracted. Recombinant human FSH (rhFSH) demonstrates higher purity and specific activity, and is suitable for subcutaneous administration. Additionally, rhFSH has facilitated the development of additional FSH products such as FSH-carboxy terminal peptide that possess different pharmacokinetic and pharmacodynamic properties and may provide more options in the treatment of ovulatory dysfunction and infertility. This article reviews the mechanism of action of FSH in folliculogenesis and ovulation, the current use of FSH in women for the medical management of infertility, and the published clinical experience to date with different rhFSH preparations.

Use of follicle-stimulating hormone for the treatment of female infertility - current concepts

Ovulatory dysfunction, which is common among women of reproductive age, often results in infertility. Over the last three decades, follicle-stimulating hormone (FSH), in the form of either urinary human menopausal gonadotropin or highly purified urinary FSH (uFSH), has been the mainstay in the treatment of women with ovulatory dysfunction. However, these preparations have several disadvantages, including variable composition, contamination with urinary proteins, and the limited availability of human menopausal urine from which uFSH is extracted. Recombinant human FSH (rhFSH) demonstrates higher purity and specific activity, and is suitable for subcutaneous administration. Additionally, rhFSH has facilitated the development of additional FSH products such as FSH-carboxy terminal peptide that possess different pharmacokinetic and pharmacodynamic properties and may provide more options in the treatment of ovulatory dysfunction and infertility. This article reviews the mechanism of action of FSH in folliculogenesis and ovulation, the current use of FSH in women for the medical management of infertility, and the published clinical experience to date with different rhFSH preparations.

The evaluation and treatment of hirsute women

Hirsutism in women is defined as an excess of body hair in the androgen-sensitive skin regions. The different genetic backgrounds of various populations may affect the causes of hirsutism. In fact, the most important reason for investigation is to identify those women with androgen-secreting tumors, since they require different therapy. Hirsutism may have various causes, such as polycystic ovary syndrome, enzyme defects in adrenal steroid biosynthesis, Cushing's syndrome, acromegaly, ovarian or adrenal tumors, or it may be idiopathic. In most patients, hirsutism is associated with hyperandrogenemia and the most common cause of androgen excess is polycystic ovary syndrome. Androgen-secreting tumors should be suspected when the onset and progression of hirsutism is rapid and/or when it is associated with virilization. Patients should be informed about the type and duration of therapy. The selection of drug/drugs depends on the severity of the hirsutism, associated conditions such as menstrual irregularities, systemic disorders such as diabetes mellitus, hypertension and any contraindication to possible therapeutic agents. Diane(R) 35 is the most common drug used for the suppression of ovarian androgen production. Peripheral blockade of androgen actions, by using spironolactone, finasteride or flutamide on the skin, is also effective in the treatment of hirsutism.

Chromium and polyphenols from cinnamon improve insulin sensitivity

Naturally-occurring compounds that have been shown to improve insulin sensitivity include Cr and polyphenols found in cinnamon (Cinnamomon cassia). These compounds also have similar effects on insulin signalling and glucose control. The signs of Cr deficiency are similar to those for the metabolic syndrome and supplemental Cr has been shown to improve all these signs in human subjects. In a double-blind placebo-controlled study it has been demonstrated that glucose, insulin, cholesterol and HbA1c are all improved in patients with type 2 diabetes following Cr supplementation. It has also been shown that cinnamon polyphenols improve insulin sensitivity in in vitro, animal and human studies. Cinnamon reduces mean fasting serum glucose (18-29%), TAG (23-30%), total cholesterol (12-26%) and LDL-cholesterol (7-27%) in subjects with type 2 diabetes after 40 d of daily consumption of 1-6 g cinnamon. Subjects with the metabolic syndrome who consume an aqueous extract of cinnamon have been shown to have improved fasting blood glucose, systolic blood pressure, percentage body fat and increased lean body mass compared with the placebo group. Studies utilizing an aqueous extract of cinnamon, high in type A polyphenols, have also demonstrated improvements in fasting glucose, glucose tolerance and insulin sensitivity in women with insulin resistance associated with the polycystic ovary syndrome. For both supplemental Cr and cinnamon not all studies have reported beneficial effects and the responses are related to the duration of the study, form of Cr or cinnamon used and the extent of obesity and glucose intolerance of the subjects.

Polycystic ovary syndrome is associated with genetic polymorphism in the insulin signaling gene IRS-1 but not ENPP1 in a Japanese population

Recent studies indicate that insulin resistance resulting from altered post-receptor signaling is associated with polycystic ovary syndrome (PCOS). We hypothesized that insulin receptor substrate-1 (IRS-1) Gly972Arg polymorphism and/or ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) Lys121Gln polymorphism predisposes women to PCOS and that these polymorphisms also affect anthropometric variables, glucose metabolism and androgen synthesis. To test those ideas, we studied the genotypes, indexes of insulin resistance, and hormone profiles in 123 Japanese women with PCOS and 380 healthy Japanese controls. We found that there were significantly more IRS-1 972Arg carriers among the PCOS patients than among the healthy controls (10.6% vs. 4.8%, p=0.029), which is consistent with our finding that women carrying the IRS-1 972Arg allele had a significantly increased risk of developing PCOS (odds ratio: 3.31, 95% confidence interval: 1.49-7.35). By contrast, the ENPP1 Lys121Arg polymorphism was distributed equally among PCOS patients and controls. In addition, neither of these polymorphisms studied affected the anthropometric variables, metabolic parameters or androgen levels of women with PCOS. We conclude that the IRS-1 Gly972Arg polymorphism is associated with PCOS in the Japanese population.