Suppression of serum insulin by diazoxide reduces serum testosterone levels in obese women with polycystic ovary syndrome

Clinical, endocrine and metabolic effects of acarbose, an alpha-glucosidase inhibitor, in PCOS patients with increased insulin response and normal glucose tolerance

BACKGROUND

The aim of this study was to evaluate whether treatment with acarbose, an alpha-glucosidase inhibitor, improved hyperandrogenic symptoms, insulin and androgen serum concentrations in hyperinsulinaemic patients with polycystic ovary syndrome (PCOS).

METHODS

30 hyperinsulinaemic women with PCOS and 15 controls were evaluated. Patients were randomized, using a computer-generated randomization list, into two groups of 15 each and treated with placebo or 300 mg/day of acarbose for three months. Hirsutism and acne/seborrhoea scores, hormonal and sex hormone binding globulin serum concentrations, glycaemia and insulin responses to a standard oral glucose load (75g) were measured in all patients before and after three months of treatment.

RESULTS

A significant reduction of the acne/seborrhoea score was observed in patients treated with acarbose and eight of them resumed a regular menstrual rhythm. These clinical improvements were associated with a significant reduction of the insulin response to glucose load, a significant decrease of LH, total testosterone and androstenedione and with a significant increase of sex hormone binding globulin serum concentrations. The serum concentrations of FSH, dehydroepiandrosterone sulphate, prolactin and 17alpha-hydroxyprogesterone did not change significantly. No clinical, metabolic and hormonal modifications were observed in PCOS patients treated with placebo.

CONCLUSIONS

This is the first report showing a reduction of the acne/seborrhoea score in hyperinsulinaemic patients with PCOS treated with acarbose. This improvement was associated with a significant decrease of the insulin response to oral glucose load and of LH and androgen serum concentrations and with a significant rise of sex hormone binding globulin concentration.

Polycystic ovarian syndrome in women with epilepsy: a review

Polycystic ovarian syndrome (PCOS) remains a controversial issue in women with epilepsy. The syndrome is characterized by clinical signs of endocrine dysfunction, such as irregular menstruation, hirsutism, and infertility, but its pathogenesis and presentation are heterogeneous. There are few data on the relationship between epilepsy and PCOS. Studies by a Finnish group have raised the issue of an association between valproate (VPA) and PCOS in young women with epilepsy. These studies, however, were retrospective, laid emphasis on polycystic ovary morphology rather than on clinical endocrine dysfunction, and were undertaken in selected populations. Further studies, both in Italy and Germany, failed to replicate the findings of the Finnish group. Future research should ideally be prospective and include baseline data in untreated women. No compelling data lead to a specific contraindication of the use of VPA in young women, and the drug remains a first-line treatment option.

Metformin directly inhibits androgen production in human thecal cells

OBJECTIVE

To examine the direct effect of metformin on thecal cell androgen production.

SETTING

Basic science research laboratory, University of Texas Southwestern, Dallas, Texas.

INTERVENTION(S)

Human ovarian theca-like tumor cells were treated with various concentrations of metformin in the presence and absence of forskolin for 48 hours.

MAIN OUTCOME MEASURE(S)

Media were collected, and radioimmunoassay (RIA) for progesterone, 17 alpha-hydroxyprogesterone (17OHP), androstenedione, and testosterone was performed. The effect of metformin on the expression of various enzymes involved in theca cell steroidogenesis was examined.

RESULT(S)

Metformin (50 microM and 200 microM) significantly inhibited androstenedione production from both forskolin-stimulated and unstimulated theca cells. Testosterone production was also significantly inhibited in forskolin-treated cells in the presence of 200 microM of metformin-treated compared with forskolin-only-treated cells. Western blot analysis revealed that metformin significantly inhibited the expression of steroidogenic acute regulatory (StAR) protein and 17 alpha-hydroxylase (CYP17) expression in cells stimulated with forskolin compared with forskolin treatment alone. There was no significant change in either 3beta-hydroxysteroid dehydrogenase (3 beta HSD) or cholesterol side-chain cleavage (CYP11A1) protein expression. Northern analysis revealed a significant decrease in the expression of CYP17 mRNA in forskolin-stimulated cells treated with metformin (200 microM) compared with forskolin-only-treated cells, however, there was no significant change in steroidogenic acute regulatory protein mRNA expression.

CONCLUSION(S)

Our results suggest that metformin may have a direct effect on thecal cells' androgen production.

Tissue insulin sensitivity and body weight in polycystic ovary syndrome

OBJECTIVE

Polycystic ovarian syndrome (PCOS) and obesity both affect insulin sensitivity. This study was designed to investigate the biochemical indices of PCOS and tissue insulin sensitivity in groups of lean and obese women with clinically equivalent degrees of the syndrome, relative to control subjects.

DESIGN

A prospective study of in vivo parameters and in vitro study of adipocytes to assess insulin sensitivity.

PATIENTS

Six lean and 14 overweight patients fulfilling formal diagnostic criteria for PCOS were studied. The degree of hirsutism and amenorrhoea was similar in each group. Eight control subjects were also studied.

MEASUREMENTS

Endocrine and metabolic parameters were measured in lean and overweight patients with PCOS and control subjects. In vitro studies of adipocyte insulin receptor binding and adipocyte insulin action were performed.

RESULTS

The mean plasma LH level was elevated in both groups of PCOS but was significantly higher in the lean group (LH levels were 25.1 +/- 3.1 and 14.5 +/- 1.6 iu/l in lean PCOS and obese PCOS, respectively (P = 0.01)). There was a strong inverse correlation between BMI and LH levels (R = - 0.70, P = 0.001). Fasting insulin levels were elevated in both lean and obese groups (11.5 +/- 2.8 and 26.8 +/- 8.1 mU/l, respectively; P = 0.068). Mean serum testosterone and serum androstenedione levels were also elevated in PCOS compared to control subjects but there was no difference between the two groups of PCOS subjects. Insulin receptor binding in amenorrhoeic subjects with PCOS was low in both lean and obese patients with PCOS but was not significantly different between the two groups (0.79 +/- 0.17% and 0.66 +/- 0.07% per 10 cm2 cell membrane, respectively). Maximally insulin-stimulated rates of 3-O-methylglucose transport were low in both groups compared to previously studied normal subjects (0.96 +/- 0.21 and 0.64 +/- 0.07 pmol per 10 cm2 membrane in lean and obese PCOS subjects, respectively; P = NS).

CONCLUSIONS

Lean subjects with a given phenotypic expression of PCOS have an equivalent degree of tissue insulin resistance compared to obese PCOS subjects. This implies that the insulin resistance may be a primary feature of PCOS. If this is so, a similar clinical degree of the syndrome may be brought about by genetically determined insulin resistance in lean subjects or by insulin resistance which is secondary to obesity.

Use of insulin-sensitizing agents in patients with polycystic ovary syndrome

OBJECTIVE

To review the subject of polycystic ovary syndrome and the therapeutic use of insulin-sensitizing agents in patients with this endocrinopathy.

METHODS

We present background information on this disorder and summarize the pertinent published literature.

RESULTS

Polycystic ovary syndrome affects approximately 7.5% of reproductive-age women in the United States. Although specific diagnostic criteria for this condition have not been established, the presence of three major factors-chronic anovulation, hyperandrogenemia, and clinical signs of hyperandrogenism-has been proposed as essential for consideration of the diagnosis. A high ratio of serum luteinizing hormone to follicle-stimulating hormone is found in 60 to 75% of women with this syndrome. Treatment with metformin may yield heterogeneous responses in differing populations with polycystic ovary syndrome, but most studies have shown evidence of restoration of ovulatory cycling. In addition, weight loss and decreases in free and total testosterone levels have been reported. Troglitazone therapy proved somewhat less efficacious than metformin for restoring menstrual cycles and similar to metformin in producing hormonal responses. Because troglitazone is no longer available for clinical use, studies will need to be extended to other thiazolidinediones. Patients treated with another insulin sensitizer, D-chiro-inositol, have demonstrated improved insulin sensitivity, ovulatory rates, and biochemical findings.

CONCLUSION

Current evidence suggests that the use of insulin-sensitizing agents in patients with polycystic ovary syndrome not only improves their sensitivity to the effects of insulin on glucose and lipid metabolism but also ameliorates clinical and biochemical manifestations of hyperandrogenism and increases rates of ovulation. Multicenter studies with larger numbers of patients are needed.

Current concepts in the polycystic ovary syndrome

Over the past 20 years, it has been clearly documented that the polycystic ovary syndrome (PCOS) has major metabolic sequelae related to insulin resistance and that insulin resistance plays an important role in the pathogenesis of the reproductive disturbances of the disorder. Family studies have indicated a genetic susceptibility to PCOS. Polycystic ovaries and hyperandrogenemia are present in approximately 50% of sisters of affected women. Increased androgen secretion and insulin resistance persist in cultured theca cells and skin fibroblasts, respectively, from women with PCOS; this finding suggests that these are intrinsic, presumably genetic, defects. Insulin resistance and elevated low-density lipoprotein (LDL) levels also cluster in the sisters of women with PCOS, consistent with genetic traits. Moreover, the brothers of women with PCOS have insulin resistance and elevated dehydroepiandrosterone sulfate (DHEAS) levels, which supports a genetic basis for these findings. Family-based studies of linkage and association have implicated several genes in the pathogenesis of PCOS. The strongest evidence to date points to a gene in the region of the insulin receptor. Insulin-sensitizing therapy mitigates the reproductive disturbances of PCOS.

Apolipoprotein E alleles in women with polycystic ovary syndrome

OBJECTIVE

To investigate the frequency of apoE alleles among women with polycystic ovary syndrome.

DESIGN

Retrospective case-control study.

SETTING

University-based endocrinology/infertility clinic.

PATIENT(S)

Healthy fertile women (n = 91) and women with a diagnosis of polycystic ovary syndrome (n = 58).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The presence of the three most common apoE alleles (epsilon2, epsilon3, and epsilon4) determined by polymerase chain reaction-restriction fragment length polymorphism in the two groups and in the general population in our area.

RESULT(S)

The frequency of the apo epsilon4 allele was 17.2% among women with polycystic ovary syndrome and was 18.7% among healthy fertile women, which is close to the rate in the general population in our area (19%). None of the apoE genotypes (Fisher's exact test; P=.71) or alleles (P=.78) was significantly overrepresented, and the homozygous genotype epsilon4 was not associated with the clinical disease.

CONCLUSION(S)

The observed profiles of allele and genotype frequencies confirm the equilibrium state between apoE polymorphism and polycystic ovary syndrome and suggest that apoE does not play a major role in the development of hyperlipidemia in the group of women with polycystic ovary syndrome.

On the association between valproate and polycystic ovary syndrome

Recent studies by Isojärvi et al. have raised the issue of an increased incidence of polycystic ovary syndrome (PCOS) in women with epilepsy treated with valproate (VPA) and have proposed replacement with lamotrigine (LTG). Polycystic ovaries (PCO) are a common finding, with a prevalence >20% in the general population, and are easily detected by pelvic or vaginal ultrasonography, whereas PCOS is comparatively rare: few women with PCO have fully developed PCOS, which includes hirsutism, acne, obesity, hypofertility. hyperandrogenemia, and menstrual disorders. From an extensive review of the current literature, it appears that there are no reliable data on the actual prevalence of PCOS in normal women and in women with epilepsy. The pathogenesis of PCO is multifactorial, including genetic predisposition and the intervention of environmental factors, among which weight gain and hyperinsulinism with insulin resistance may play a part. The roles of central (hypothalamic/pituitary), peripheral, and local ovarian factors are still debated. PCO and PCOS appear to be more frequent in women with epilepsy, but there are no reliable data showing a greater prevalence after VPA. The recent studies by Isojärvi et al. may have been biased by the retrospective selection of patients. To date, there is no reason to contraindicate the use of VPA in women with epilepsy. However, patients should be informed about the risk of weight gain and its consequences.

Polycystic ovary syndrome, hyperandrogenism, and insulin resistance

Results from recent basic and clinical research investigations have greatly improved our understanding of insulin resistance in general and insulin resistance associated with PCOS in particular. With this understanding has come the possibility of using new methods to treat PCOS. This is particularly true when discussing the use of insulin-sensitizing drugs. Caution must be exercised in using these drugs because of unforeseen acute or remote adverse side effects. Postulated relationships among PCOS, hyperandrogenism, and insulin resistance do not completely solve the endocrinologic mystery of the patient with PCOS. For example, how does the partial destruction of the ovary (e.g., wedge biopsy or ovary drilling by laser or cautery), which does not affect insulin resistance, result in ovulatory cycles? Why does the administration of excessive exogenous insulin in the case of the insulin-dependent diabetic fail to cause hyperandrogenism? Certainly, much remains to be learned about the reproductive endocrine disturbance we now call PCOS.

Insulin-lowering drugs in polycystic ovary syndrome

The discovery that insulin resistance has a key role in the pathophysiology of PCOS has led to a novel and promising form of therapy in the form of the insulin-sensitizing drugs. Although no extremely large trials using these drugs for this indication have been performed, more than 18 trials have specifically examined the effects of these drugs on ovulation, hyperandrogenemia, and dysmetabolic features in PCOS. Table 1 summarizes the results of previous trials using each of the insulin-sensitizing drugs discussed herein. Among the various agents (i.e., thiazolidinediones, [table: see text] metformin, and D-chiro-inositol), metformin is the most widely tested. Metformin may have the added benefit of improving at least some features of syndrome X, such as hypertension and obesity. All of the evidence to date suggests that metformin is a safe drug to administer to women who may become pregnant. In contrast, the two thiazolidinediones currently available, rosiglitazone and pioglitazone, are category C drugs that have been demonstrated to retard fetal development in animal studies. Overall, insulin-sensitizing therapy presents a promising and unique therapeutic intervention for the treatment of PCOS, offering metabolic and gynecologic benefits for women who sustain this syndrome.

Early metabolic abnormalities in adolescent girls with polycystic ovarian syndrome

OBJECTIVE

To investigate insulin sensitivity and secretion in young adolescent girls with childhood onset polycystic ovarian syndrome (PCOS) and to identify the early metabolic derangement(s).

STUDY DESIGN

Twelve obese girls with PCOS (age 12.0+/-0.7 years) were compared with 10 obese nonhyperandrogenic girls (control group). The groups were matched for age, percent body fat, and abdominal fat. All subjects underwent a 3-hour hyperinsulinemic (80 mu/m(2)/min)-euglycemic clamp to determine in vivo insulin sensitivity and a 2-hour hyperglycemic clamp (225 mg/dL) to determine insulin secretion. Fasting hepatic glucose production was determined with the use of [6,6-(2)H(2)]glucose.

RESULTS

Fasting glucose and hepatic glucose production were comparable between the 2 groups, but fasting insulin was 2-fold higher in the PCOS group. The fasting glucose to insulin ratio was lower in the PCOS group versus the control group (1.9+/- 0.3 vs 3.1+/-0.3, P =.02). During the hyperinsulinemic-euglycemic clamp, insulin sensitivity was lower in the PCOS group (1.4+/-0.2 vs 2.7+/-0.3 mg/kg/min per microu/mL, P =.002). During the hyperglycemic clamp, insulin secretion was significantly higher in the PCOS group. Insulin sensitivity correlated negatively with fasting insulin (r = -0.71, P =.0002) and positively with the fasting glucose to insulin ratio (r = 0.79, P<.0001).

CONCLUSION

Adolescent girls with PCOS have profound metabolic derangements detected early in the course of the syndrome, including (1) approximately 50% reduction in peripheral tissue insulin sensitivity, (2) evidence of hepatic insulin resistance, and (3) compensatory hyperinsulinemia. These observations may predict an increased risk of type 2 diabetes mellitus in adolescents with PCOS.

Premature adrenarche--normal variant or forerunner of adult disease?

Adrenarche is the puberty of the adrenal gland. The descriptive term pubarche indicates the appearance of pubic hair, which may be accompanied by axillary hair. This process is considered premature if it occurs before age 8 yr in girls and 9 yr in boys. The chief hormonal product of adrenarche is dehydroepiandrosterone (DHEA) and its sulfated product DHEA-S. The well documented evolution of adrenarche in primates and man is incompatible with either a neutral or harmful role for DHEA and implies most likely a positive role for some aspect of young adult pubertal maturation and developmental maturation. Premature adrenarche has no adverse effects on the onset and progression of gonadarche in final height. Both extra- and intraadrenal factors regulate adrenal androgen secretion. Recent studies have shown that premature adrenarche in childhood may have consequences such as functional ovarian hyperandrogenism, polycystic ovarian syndrome, and insulin resistance in later life, sometimes already recognizable in childhood or adolescence. Premature adrenarche may thus be a forerunner of syndrome X in some children. The association of these endocrine-metabolic abnormalities with reduced fetal growth and their genetic basis remain to be elucidated.

High prevalence of the polycystic ovary syndrome and hirsutism in women with type 1 diabetes mellitus

The current recommendation for strict metabolic control of type 1 diabetes mellitus requires the administration of supraphysiological doses of insulin, which might result in insulin-mediated stimulation of androgen synthesis, as occurs in insulin-resistant states. At present, the prevalence of hyperandrogenic disorders in women with type 1 diabetes mellitus is unknown. Eighty-five women with type 1 diabetes mellitus were evaluated for symptoms and signs of hyperandrogenism. In 68 of the patients, several serum androgen and hormone concentrations were measured. The polycystic ovary syndrome (PCOS) was defined by the presence of menstrual dysfunction, together with clinical and/or biochemical evidence of hyperandrogenism, and exclusion of other etiologies. Eighteen healthy women, menstruating regularly, served as controls for the androgenic profiles. Thirty-three patients (38.8%) presented hyperandrogenic disorders (16 had PCOS, and 17 had hirsutism without menstrual dysfunction). Type 1 diabetic patients with PCOS presented increased serum total and free testosterone concentrations, and serum androstenedione levels, but had normal serum sex hormone-binding globulin and dehydroepiandrosterone-sulfate levels. Hirsute type 1 diabetic women without menstrual dysfunction presented normal serum androgen levels. There were no significant differences between hyperandrogenic and nonhyperandrogenic type 1 diabetes mellitus women in clinical variables such as the duration of diabetes, age at diagnosis of diabetes, conventional or intensive insulin therapy, mean daily insulin dosage, or metabolic control. In conclusion, women with type 1 diabetes mellitus have a high prevalence of hyperandrogenic disorders, including PCOS and hirsutism.

Sensitization to insulin in adolescent girls to normalize hirsutism, hyperandrogenism, oligomenorrhea, dyslipidemia, and hyperinsulinism after precocious pubarche

Precocious pubarche in girls is often preceded by low weight at birth and followed by hirsutism, ovarian hyperandrogenism, and oligomenorrhea in adolescence, the latter usually being accompanied by dyslipidemia and hyperinsulinism, which are, in turn, two major risk factors for cardiovascular disease in later life. We hypothesized that insulin resistance may be a key pathogenetic factor in this sequence. We tested the hypothesis by assessing the effects of an insulin-sensitizing agent, metformin, given at a daily dose of 1275 mg for 6 months to 10 nonobese adolescent girls (mean age, 16.8 yr; body mass index, 21.9 kg/m2; birth weight, 2.7 kg) with hirsutism, ovarian hyperandrogenism (diagnosis by GnRH agonist test), oligomenorrhea, dyslipidemia, and hyperinsulinemia after precocious pubarche. Before the metformin trial, longitudinal studies in these girls had shown that hyperinsulinism was present at prepubertal diagnosis of precocious pubarche, and that it increased markedly in late puberty or early postmenarche. Metformin treatment was well tolerated and was accompanied by a marked drop in hirsutism score, insulin response to oral glucose tolerance test, free androgen index, and baseline testosterone, androstenedione, dehydroepiandrosterone, and dehydroepiandrosterone sulfate levels (all P < 0.01). During metformin treatment, the LH and 17-hydroxyprogesterone hyperresponses to GnRH agonist were attenuated (P < 0.01); serum triglyceride, total cholesterol, and low density lipoprotein cholesterol levels decreased; and high density lipoprotein cholesterol rose. All girls reported regular menses within 4 months. Withdrawal of metformin treatment was followed, within 3 months, by a consistent reversal toward pretreatment conditions. In conclusion, metformin treatment reduced hyperinsulinemia, hirsutism, and hyperandrogenism; attenuated the LH and 17-hydroxyprogesterone hyperresponses to GnRH agonist; improved the atherogenic lipid profile; and restored eumenorrhea in nonobese adolescent girls with a history of precocious pubarche. These observations corroborate the idea that insulin resistance may indeed be a prime factor underpinning the sequence from reduced fetal growth, through precocious pubarche, to adolescent endocrinopathies that are reminiscent of so-called polycystic ovary syndrome.

Insulin-lowering medications in polycystic ovary syndrome

A growing body of evidence suggests that serum hyperinsulinemia contributes to the excess ovarian androgen secretion observed in women with PCOS. As a group, women with PCOS are hyperinsulinemic and insulin resistant when compared with weight-matched normal women, but not all PCOS subjects display clear metabolic defects. The small studies using insulin-sensitizing drugs have demonstrated conclusively that a reduction in serum insulin levels is associated with a reduction of ovarian androgen secretion in PCOS, providing further evidence that hyperinsulinemia contributes to hyperandrogenism by increasing ovarian androgen secretion and reducing SHBG. The improvement of serum androgen levels with multiple different drug classes with different mechanisms of actions suggests an effect mediated by reduction in circulating insulin levels rather than a direct ovarian effect of the drugs. Although the studies published to date have increased understanding of the pathophysiologic mechanisms of PCOS, before these drugs can be recommended as first-line therapy for women, longer term clinical trials are needed to compare their safety and efficacy with other established therapies, such as oral contraceptive pills and antiandrogens. Because of the potential direct and unique beneficial effects of these medications on metabolism, studies must be performed to evaluate their efficacy in combination with other therapies, especially oral contraceptives. It is likely that subsets of patients who cannot tolerate traditional medications will be better managed with insulin sensitizers as first-line therapy; however, to date, the optimal way to identify these subjects is unknown. Whether therapy should be limited to subjects with documented hyperinsulinemia also remains unknown.

Effect of long-term treatment with metformin added to hypocaloric diet on body composition, fat distribution, and androgen and insulin levels in abdominally obese women with and without the polycystic ovary syndrome

Abdominal obesity and hyperinsulinemia play a key role in the development of the polycystic ovary syndrome (PCOS). Dietary-induced weight loss and the administration of insulin-lowering drugs, such as metformin, are usually followed by improved hyperandrogenism and related clinical abnormalities. This study was carried out to evaluate the effects of combined hypocaloric diet and metformin on body weight, fat distribution, the glucose-insulin system, and hormones in a group of 20 obese PCOS women [body mass index (BMI) > 28 kg/m2] with the abdominal phenotype (waist to hip ratio >0.80), and an appropriate control group of 20 obese women who were comparable for age and pattern of body fat distribution but without PCOS. At baseline, we measured sex hormone, sex hormone-binding globulin (SHBG), and leptin blood concentrations and performed an oral glucose tolerance test and computerized tomography (CT) at the L4-L5 level, to measure sc adipose tissue area (SAT) and visceral adipose tissue area. All women were then given a low-calorie diet (1,200-1,400 kcal/day) alone for one month, after which anthropometric parameters and CT scan were newly measured. While continuing dietary treatment, PCOS women and obese controls were subsequently placed, in a random order, on metformin (850 mg/os, twice daily) (12 and 8, respectively) or placebo (8 and 12, respectively), according to a double-blind design, for the following 6 months. Blood tests and the CT scan were performed in each woman at the end of the study while they were still on treatment. During the treatment period, 3 women of the control group (all treated with placebo) were excluded because of noncompliance; and 2 PCOS women, both treated with metformin, were also excluded because they became pregnant. Therefore, the women cohort available for final statistical analysis included 18 PCOS (10 treated with metformin and 8 with placebo) and 17 control women (8 treated with metformin and 9 with placebo). The treatment was well tolerated. In the PCOS group, metformin therapy improved hirsutism and menstrual cycles significantly more than placebo. Baseline anthropometric and CT parameters were similar in all groups. Hypocaloric dieting for 1 month similarly reduced BMI values and the waist circumference in both PCOS and control groups, without any significant effect on CT scan parameters. In both PCOS and control women, however, metformin treatment reduced body weight and BMI significantly more than placebo. Changes in the waist-to-hip ratio values were similar in PCOS women and controls, regardless of pharmacological treatment. Metformin treatment significantly decreased SAT values in both PCOS and control groups, although only in the latter group were SAT changes significantly greater than those observed during the placebo treatment. On the contrary, visceral adipose tissue area values significantly decreased during metformin treatment in both PCOS and control groups, but only in the former was the effect of metformin treatment significantly higher than that of placebo. Fasting insulin significantly decreased in both PCOS women and controls, regardless of treatment, whereas glucose-stimulated insulin significantly decreased only in PCOS women and controls treated with metformin. Neither metformin or placebo significantly modified the levels of LH, FSH, dehydroepiandrosterone sulphate, and progesterone in any group, whereas testosterone concentrations decreased only in PCOS women treated with metformin. SHBG concentrations remained unchanged in all PCOS women; whereas in the control group, they significantly increased after both metformin and placebo. Leptin levels decreased only during metformin treatment in both PCOS and control groups. (ABSTRACT TRUNCATED)

Metformin therapy decreases hyperandrogenism and hyperinsulinemia in women with polycystic ovary syndrome

OBJECTIVE

To evaluate the effects of 12 weeks of metformin therapy on hormonal and clinical indices in polycystic ovary syndrome (PCOS).

DESIGN

Prospective study.

SETTING

University hospital.

PATIENT(S)

Thirty-nine women with PCOS and fasting hyperinsulinemia.

INTERVENTION(S)

Twelve weeks of therapy with oral metformin (500 mg three times per day).

MAIN OUTCOME MEASURE(S)

Levels of insulin, T, DHEAS, insulin-like growth factor-I (IGF-I), gonadotropins, and sex hormone-binding globulin (SHBG); and clinical symptoms including acne, hirsutism, and length of the menstrual cycle were assessed before and after treatment with metformin.

RESULT(S)

Metformin therapy resulted in a significant decrease in fasting insulin and total T and an increase in SHBG, leading to a decrease in the free T index. In addition, there was a significant decline in mean body mass index, waist-hip ratio, hirsutism, and acne, as well as an improvement in the menstrual cycle. No changes in LH and LH-FSH ratio were observed. Multiple regression analysis demonstrated that the greatest decline of T and free T index in response to metformin was observed among patients with the most pronounced hyperandrogenemia. Subjects with elevated DHEAS differed from those with normal DHEAS in their responses to metformin treatment. Women with high DHEAS exhibited less improvement of menstrual cycle regularity, no change in hirsutism, and an increase in levels of IGF-I after treatment.

CONCLUSION(S)

Metformin treatment of women with PCOS results in a decline of insulin as well as total and bioavailable T, leading to significant improvement of clinical manifestations of hyperandrogenism. Responses to metformin are related to the severity of hyperandrogenemia and to adrenal function.

Insulin sensitizer, troglitazone, directly inhibits aromatase activity in human ovarian granulosa cells

Ovarian granulosa cells synthesize estrogens from androgens, which are catalyzed by aromatase cytochrome P450 (P450arom). Troglitazone (Tro), one of the insulin-sensitizing compounds, thiazolidinediones (TZDs), is a ligand for peroxisome proliferator activated receptor gamma (PPARgamma) and is effective in the treatment of both non-insulin-dependent diabetes mellitus (NIDDM) as well as polycystic ovary syndrome (PCOS). PPARgamma exerts a transcriptional activity as a PPARgamma:RXR heterodimer. In this study, we investigated the effects of Tro and/or RXR ligand, LG100268 (LG) on the aromatase activity in cultured human ovarian granulosa cells obtained from patients who underwent in vitro fertilization. Human ovarian granulosa cells expressed PPARgamma mRNA assessed by RT-PCR. The treatment of the granulosa cells with Tro for 24 h resulted in a dramatic inhibition of the aromatase activity in a dose-dependent manner. While the treatment with LG alone also inhibited the aromatase activity, the combined treatment with both Tro and LG caused a much more reduction in the aromatase activity. The changes in the aromatase activity by Tro and/or LG were associated with comparable changes in P450arom mRNA assessed by RT-PCR. These results suggest that Tro directly inhibit the aromatase activity in human granulosa cells probably via nuclear receptor system PPARgamma:RXR heterodimer. The findings may provide a biochemical basis for the decrease in the blood concentrations of estrogens which is observed after the in vivo administration of Tro and may also possibly be useful as a novel therapy for estrogen-dependent diseases.

Hyperinsulinism and its interaction with hyperandrogenism in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age. It has become increasingly evident that insulin resistance plays a significant role both as a cause and result of the syndrome. The purpose of this review is to summarize the possible mechanisms leading to insulin resistance and resultant hyperinsulinism (HI) and their interaction with hyperandrogenism (HA) in PCOS. We conducted a computerized search of MEDLINE for relevant studies in the English literature published between January 1966 and January 2000. We reviewed all studies that investigated the roles of insulin, insulin receptor, and insulin gene in insulin resistance and its interaction with hyperandrogenism in PCOS. Insulin resistance in PCOS seems to involve a postbinding defect in the insulin receptor and/or in the receptor signal transduction. Current research has focused on identifying a genetic predisposition for insulin resistance in this syndrome. The answer to the question whether HI or HA is the initiating event is still unclear inasmuch as there are clinical and molecular evidences to support both of these approaches. Our view is that whichever is the triggering insult, a vicious cycle is established where HI acts to aggravate HA and vice versa. In this model, obesity and genetic predisposition seem to be the independent factors that can give rise or contribute to HI, HA, or both simultaneously. It seems that "hyperinsulinemic hyperandrogenism" represents a significant subgroup of PCOS, which probably needs to be renamed and reclassified in the light of this new approach.

Clinical presentation of PCOS following development of an insulinoma: case report

A 24 year old woman presented with a prolonged clinical history of fasting and exertional hypoglycaemia, and was subsequently diagnosed with an insulinoma. Concurrent symptoms of oligomenorrhoea and hyperandrogenism of similar duration were noted. Biochemically, hyperinsulinaemia was observed in association with a raised serum luteinizing hormone (LH), raised testosterone and androstendione concentrations. Surgical removal of the insulinoma resulted in resolution of the clinical and biochemical features of the polycystic ovarian syndrome (PCOS) but minimal change was observed in the ovarian ultrasound appearances. This case demonstrates the role of insulin in mediating the hypersecretion of both LH and androgens in women with polycystic ovaries. We suggest that hyperinsulinaemia converted occult 'polycystic ovaries' to become clinically manifest as 'polycystic ovary syndrome'. This paradigm has clear implications for women with insulin dependent diabetes mellitus who presumably have systemic hyperinsulinaemia.

Metformin treatment reduces ovarian cytochrome P-450c17alpha response to human chorionic gonadotrophin in women with insulin resistance-related polycystic ovary syndrome

It has recently been proposed that hyperinsulinaemic insulin resistance and increased ovarian cytochrome P-450c17alpha activity, two features of the polycystic ovary syndrome (PCOS), are pathogenetically linked. The aim of the present study was to test the hypothesis of the linkage between hyperinsulinaemia and supranormal activity of cytochrome P-450c17alpha using the human chorionic gonadotrophin (HCG) challenge, which is a more direct ovarian stimulus than gonadotrophin-releasing hormone (GnRH) in detecting modifications in ovarian steroidogenesis. Eleven women with insulin resistance-related PCOS were studied. HCG (10 000 IU) was given i.m., and blood samples were obtained 0, 8, 12, 16 and 24 h thereafter. Next day, metformin was given at a dose of 500 mg three times a day for 30-32 days, at which time the pretreatment study was repeated. Two women ovulated after metformin treatment. The administration of metformin was associated with a decrease in area under the curve for insulin during a 2h, 75g oral glucose tolerance test, in plasma free testosterone concentrations and an increase in plasma sex hormone binding globulin concentration. The plasma 17-hydroxyprogesterone response to HCG was significantly lower after metformin treatment. The present study gives a direct demonstration that metformin leads to a reduction in stimulated ovarian cytochrome P-450c17alpha activity in women with polycystic ovary syndrome.

Endocrine and metabolic effects of octreotide, a somatostatin analogue, in lean PCOS patients with either hyperinsulinaemia or lean normoinsulinaemia

The effects on insulin secretion and on the glycaemic and androgen status before and after short-term treatment with octreotide were evaluated in 16 normal weight patients with polycystic ovarian syndrome (PCOS). Hyperinsulinaemia was determined by measuring the insulin response after oral glucose tolerance test (OGTT). Seven patients (group A) were classified as normoinsulinaemic, while nine patients (group B) were considered hyperinsulinaemic according to insulin response after OGTT. Octreotide treatment did not modify either glycaemic or insulinaemic response after OGTT, or androgen profile, in normoinsulinaemic patients. On the contrary, a significant decrease in the basal concentrations of luteinizing hormone (LH), testosterone and androstenedione, and a significant increase in serum concentrations of sex hormone-binding globulin (SHBG) were observed in the hyperinsulinaemic group of patients, in which we observed also a significant decrease of insulinaemic response and a decompensation of the glycaemic profile after OGTT. Our study is the first report showing that: (i) octreotide does not appear to significantly influence pituitary release of gonadotrophins in this group of PCOS patients; (ii) octreotide is able to reduce insulin release, LH and androgen concentrations in lean PCOS patients with hyperinsulinaemia. Due to the presence of a decompensation of glucose homeostasis during treatment, octreotide does not seem advisable for long-term therapy of hyperandrogenism in lean PCOS patients with hyperinsulinaemia.

Effects of the insulin sensitizing drug metformin on ovarian function, follicular growth and ovulation rate in obese women with oligomenorrhoea

Hyperinsulinaemic insulin resistance is commonly associated with hyperandrogenaemia, and menstrual dysfunction. The aim of this study was to examine the effects of the insulin sensitizing drug, metformin, on ovarian function, follicular growth, and ovulation rate in obese women with oligomenorrhoea. Twenty obese subjects with oligomenorrhoea [polycystic ovarian syndrome; (PCOS)] were observed longitudinally for 3 weeks prior to and for 8 weeks during treatment with metformin (850 mg twice per day). Fifteen patients completed the study. The frequency of ovulation was significantly higher during treatment than before treatment (P = 0.003). A significant decline in both testosterone and luteinizing hormone concentrations was recorded within 1 week of commencing treatment. Patients with elevated pretreatment testosterone concentrations showed the most marked increase in ovulation rate (P < 0.005), and significant reductions in circulating testosterone from 1.02 to 0.54 ng/ml (P < 0.005) after only 1 week of treatment. However, the sub-group with raised fasting insulin showed less marked changes, and the sub-group with normal testosterone concentrations showed no effect of treatment. Metformin had a rapid effect upon the abnormal ovarian function in hyperandrogenic women with PCOS, correcting the disordered ovarian steroid metabolism and ovulation rate; however, there appeared to be no effect in cases where the circulating androgen concentration was normal.

The effects of metformin on insulin resistance and ovarian steroidogenesis in women with polycystic ovary syndrome

OBJECTIVE

Polycystic ovary syndrome (PCOS) is a form of functional ovarian hyperandrogenism and affects approximately 5-10% of women of reproductive age. Insulin resistance and hyperinsulinaemia appear to be almost universal feature of the polycystic ovary syndrome. Abnormal regulation of cytochrome P450c17alpha causes the exaggerated secretion of ovarian androgens in PCOS. The aim of the present study was to determine whether reduction of insulin levels by metformin would attenuate FSH, LH, 17-Hydroxyprogesterone (17-OHP) and androstenedione hyperresponsiveness to buserelin testing in PCOS women.

DESIGN

The presence of hyperinsulinaemia in 16 women with PCOS was demonstrated by an oral glucose tolerance test (OGTT) and results were compared with 13 healthy women. PCOS women were also evaluated with insulin tolerance test (ITT) for the assessment of insulin sensitivity. FSH, LH, 17-OHP and androstenedione responses to buserelin testing were measured in all the women with PCOS. PCOS patients were given metformin (500 mg, orally, two times daily) for 12 weeks and re-evaluated at the end of the treatment period.

RESULTS

Women with PCOS were hyperinsulinaemic (basal insulin 92.1+/-14.3 vs. 44.0+/-4.0 pmol/l; AUCinsulin 68087.4+/-8862.3 vs. 13075.5+/-1327.6 pmol/lx120 min) compared with healthy women. Metformin therapy improved menstrual disturbances in 25% of the women with PCOS and also resulted in some improvement in insulin sensitivity and reduced basal and post glucose load insulin levels. However, FSH, LH, 17-OHP and androstenedione responses to buserelin testing were unaltered in response to metformin.

CONCLUSION

It is clear that PCOS is often associated with profound insulin resistance and hyperinsulinaemia. These abnormalities explain the increased prevalence of glucose intolerance in women with PCOS and metformin has beneficial effects on insulin sensitivity in women with PCOS. Amelioration of hyperinsulinaemia has no significant effect on ovarian cytochrome P450c17alpha enzyme activity. However, it can be used in obese women with PCOS as an adjuvant therapy and long term studies should be performed to evaluate the endocrine effects of metformin in women with PCOS.

Ovarian responses to hCG stimulation: insulin resistance/hyperinsulinaemia vs. insulin deficiency

Polycystic ovary syndrome is a heterogeneous disorder characterized by signs and symptoms of hyperandrogenism and insulin resistance. We present the clinical and hormonal features in an adolescent girl who had distinct intervals of insulin deficiency and insulin resistance/hyperinsulinaemia. This case report confirms that insulin resistance/hyperinsulinaemia exacerbates ovarian hyperandrogenism.

Insulin-lowering therapeutic modalities for polycystic ovary syndrome

This article summarizes the relationship between insulin and androgen excess, with a focus on what is known regarding two related issues in polycystic ovary syndrome: (1) defects in insulin secretion in PCOS and their role in the development of glucose intolerance in this population; and (2) pharmacologic interventions designed to attenuate hyperinsulinemia and its sequelae in PCOS.

Insulin action in the polycystic ovary syndrome

Research on insulin action in PCOS has been intensive after the identification of insulin resistance as a feature of the syndrome in 1980. It is now clear that PCOS is a metabolic as well as a reproductive disorder and an important cause of type 2 diabetes mellitus in women. The cellular and molecular mechanisms of insulin resistance in PCOS are distinct from those in other insulin resistance syndromes. Elucidating these mechanisms promises to provide considerable insight into insulin receptor signal specificity. Conversely, insulin resistance is now known to have an important role in the pathogenesis of the reproductive disturbances of PCOS. It is thought that one or several genetic defects may cause both the insulin resistance and reproductive abnormalities characteristic of PCOS.

Inositolphosphoglycans (IPGs) as mediators of insulin's steroidogenic actions

PCOS is a unique model of insulin resistance in which one tissue (skeletal muscle) is resistant to insulin in terms of glucose metabolism whereas another tissue (ovarian thecal cells) maintains its responsiveness to insulin in terms of testosterone biosynthesis. During the past decade, a series of in vitro studies conducted in human placental cells /25/, swine granulosa cells /28/, and most recently, human thecal cells /17/, have provided compelling evidence that one factor involved in this apparent clinical paradox is the clear demonstration of the utilization of the IPG signal transduction system for insulin's effects on steroidogenesis. Nonetheless, many questions remain to be addressed. For example, it would be instructive to determine simultaneously the effects of insulin on glucose disposal and testosterone biosynthesis in isolated thecal cells. In other words, is the thecal cell itself resistant to insulin in terms of glucose disposal while remaining sensitive to insulin in terms of testosterone biosynthesis? Is the IPG content of human thecal cells from women with PCOS decreased compared with that in matched healthy women? There is substantial evidence to suggest that some IPGs may also be responsible in part for mediating insulin's stimulation of glucose disposal (see paper by Dr. Joseph Larner in this issue)--this raises the question as to whether specific forms of IPGs are responsible for glucose metabolism in vivo, whereas other IPGs are responsible for mediating insulin's effects on steroidogenesis. Is there a disparity in the ratio of different types of IPGs among various tissues (e.g., muscle, liver, ovary), and does that ratio determine the tissue's responsiveness to one or another action of insulin? These questions and others leave IPGs and insulin signal transduction a fruitful area for both clinical and laboratory investigations.

The natural history of the metabolic syndrome in young women with the polycystic ovary syndrome and the effect of long-term oestrogen-progestagen treatment

OBJECTIVE

Little is known about the natural history of polycystic ovary syndrome (PCOS), although preliminary data indicate that affected women are more susceptible than the general population to diabetes and cardiovascular diseases at post-menopausal ages. The aim of this study was to follow-up all main features of the metabolic syndrome in a group of young women with PCOS and to investigate the long-term effects on metabolism and body composition of oestrogen-progestagen (OP) compounds, which are frequently used in these women to treat hyperandrogenism and related clinical features.

DESIGN

Long-term follow-up study.

SUBJECTS AND METHODS

Thirty-seven women with PCOS were re-evaluated 10.3 +/- 0.8 years (range 6-18 years) after their first assessments (age: before 19.8 +/- 4.9 years; after 29.9 +/- 4.4 years). When first examined, women were instructed to follow a hypocaloric diet if they were obese plus OP, if they agreed to such treatment. Main anthropometric parameters, basal sex hormones and lipids, fasting and glucose-stimulated glucose and insulin levels and several clinical data were recorded before and after follow-up.

RESULTS

In the whole group of women with PCOS we found no changes in body weight and fat mass, whereas both the waist-to-hip ratio and the waist-to-thigh ratio were significantly reduced. No significant changes occurred in mean fasting and glucose-stimulated glucose and insulin concentrations, whereas a significant increase in high-density lipoprotein-cholesterol was found. No significant changes occurred in testosterone levels. During the follow-up period 16 women took OP for an average of 97 +/- 18 months (range 12-180 months) (OP-users) whereas 21 women never took OP (non-OP-users). All OP-users were still taking OP when re-evaluated at the follow-up examination. With respect to baseline values, body mass index was higher in non-OP-users than in their counterparts. Waist circumference (P < 0.025), the waist-to-hip (P < 0.05) and the waist-to-thigh (P < 0.01) ratios decreased significantly only in the OP-users. In addition, percentage changes in waist circumference (P < 0.05) and waist-to-hip ratio (P < 0.05) during the follow-up period were significantly different between the groups. Glucose tolerance (as area under the curve (AUC)) improved (P < 0.05) in OP-users but not in non-OP-users. Moreover, compared to baseline values, basal insulin levels were significantly (P < 0.01) reduced in OP-users but not in non-OP-users. On the contrary, no significant change was found in insulinAUC in the former, whereas it significantly increased (P < 0.05) in the latter. Accordingly, fasting C-peptide decreased (P < 0.05) in OP-users, whereas both fasting (P < 0.01) and stimulated (P < 0.01) C-peptide significantly increased in non-OP-users. Changes in fasting or stimulated insulin and C-peptide in non-OP-users were not associated with parallel changes in testosterone levels. Total cholesterol and triglycerides did not change in either group, but HDL-cholesterol increased (P < 0.05) only in OP-users. Sex hormone-binding globulin concentrations increased significantly (P < 0.01) in OP-users, without any significant change in non-OP-users. Testosterone concentrations did not change significantly in either group, but the testosterone: SHBG ratio significantly decreased in OP-users (P < 0.05) but not in the non-OP-users. Among the clinical features, acanthosis nigricans significantly (P < 0.01) worsened in non-OP-users but not in the OP-users, without any significant change in the hirsutism and acne scores. Pregnancy rates during the follow-up were similar in both groups.

CONCLUSIONS

These data indicate that hyperinsulinaemia and insulin resistance tended to worsen spontaneously in women with PCOS, without any worsening of the hyperandrogenism. Long-term oestrogen-progestagen treatment countered this tendency, probably because it improved the pattern of body fat distribution, by reducing abdominal fat depots.

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.

Hyperinsulinism and sex hormones in young adult African Americans

Hyperinsulinemia is a risk factor for cardiovascular disease, and is linked with non-insulin-dependent diabetes mellitus (NIDDM), hyperlipidemia, obesity, and hypertension. Sex hormones also play a role in the metabolic alterations associated with the risk for cardiovascular disease. A reduction in sex hormone-binding globulin (SHBG) may be predictive of future NIDDM particularly in women. The postmenopausal decline in estrogen is also associated with an increase in risk factor expression in women. Since African Americans experience a greater prevalence of NIDDM, obesity, and hypertension, conditions associated with hyperinsulinemia, the purpose of this study was to determine if alterations in sex hormone levels are associated with the plasma insulin concentration in young adult African Americans, and to determine if there are sex differences in the effect of insulin on lipids and sex hormones. In a sample of 221 nondiabetic African American men (n = 105) and women (n = 116) with a mean age of 31 years, we examined the relationship of the plasma insulin concentration with the body mass index (BMI), blood pressure, plasma lipids, and sex hormones, including free testosterone, estradiol, and SHBG. Plasma insulin increased with the BMI and other measures of adiposity (P<.001) in men and women. Significant correlations of insulin with plasma lipids were also present in both sexes. There was a significant inverse correlation of insulin with SHBG in both men (r = .28, P = .007) and women (r = .27, P = .02). There was a significant direct correlation of insulin with free testosterone in women (r = .032, P<.001). Stepwise multiple regression analyses with insulin as the dependent variable detected the BMI, triglyceride, and apolipoprotein A1 as significant contributors to the plasma insulin concentration in men. In women, the multiple regression model detected percent body fat, low-density lipoprotein (LDL) cholesterol, and free testosterone as significant contributors to plasma insulin. These data on young African Americans demonstrate a significant relationship between hyperinsulinemia and obesity, atherogenic lipid status, and lower SHBG. In the premenopausal women, the lower SHBG is linked with higher free testosterone, favoring a condition of relative androgen excess.

Polycystic ovary syndrome

Polycystic ovary syndrome is a syndrome and not a disease. It reflects multiple potential etiologies and variable clinical presentations that are reviewed in this article. In addition to menstrual dysfunction and hyperandrogenism, women with polycystic ovary syndrome also may have hypothalamic-pituitary abnormalities, polycystic ovaries on pelvic ultrasonography, infertility, obesity, and insulin resistance. A familial pattern occurs in some cases, suggesting a genetic component to the disorder. The three major pathophysiologic hypotheses that have been proposed to explain the clinical findings of the disorder as well as treatment options are reviewed in this article.

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.

Polycystic ovary syndrome: symptomatology, pathophysiology, and epidemiology

Women with polycystic ovary syndrome seek health care for 3 major reasons: infertility, menstrual irregularity, and androgen excess. The infertility is associated with anovulation. The menstrual irregularity is typically chronic, beginning with menarche. Although amenorrhea may sometimes occur, the more common presentation is irregular bleeding characteristic of anovulation. Androgen excess may be manifested by varying degrees of hirsutism. Patients may also report acne. The rapid development of virilizing signs, such as deepening of the voice, increased muscle mass, and temporal balding, should prompt a search for a tumor and lead one away from a diagnosis of polycystic ovary syndrome. Typically treatment is directed at alleviating the symptoms: ovulation induction for infertility, oral contraceptives or a progestin for menstrual irregularity, and oral contraceptives or spironolactone for hirsutism. On the basis of recent epidemiologic data suggestive of increased cardiovascular risk among women with polycystic ovary syndrome, such treatment might be complemented by a long-term approach that addresses the underlying pathophysiology of insulin resistance.

Role of cytochrome P450c17 in polycystic ovary syndrome

The hyperandrogenism of polycystic ovary syndrome (PCOS) appears to be due to dysregulation of steroidogenesis within the ovaries and adrenal glands. P450c17 is the key enzyme that regulates androgen synthesis. It is the only enzyme known to have the capacity to convert C21-precursors to the androgen pre-hormones, the 17-ketosteroids. It is a single enzyme with two activities, 17-hydroxylase and 17,20-lyase. Thus, its regulation is a significant factor in the expression of hyperandrogenism. Androgen secretion is LH-dependent in the ovary and ACTH-dependent in the adrenal glands. The androgenic response to each of these tropic hormones seems to be modulated by intra-ovarian or intra-adrenal autocrine and paracrine mechanisms. This modulation serves to regulate steroid hormone secretion in tissue-specific ways. Insulin, IGFs and inhibin are among the many growth factors capable of augmenting the response to LH and ACTH. The insulin/IGF system stimulates P450c17 mRNA expression and activities in the ovaries and adrenal glands. An integrating link between insulin resistance and hyperandrogenemia may be serine phosphorylation, which inhibits activity of the insulin receptor and promotes the 17,20-lyase activity of P450c17. However, it must be kept in mind that there is some evidence for the existence of P450c17-independent pathways of androgen biosynthesis.

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.

The pathogenesis of polycystic ovary syndrome: lessons from ovarian stimulation studies

In polycystic ovary syndrome (PCOS) the ovary produces markedly increased amounts of both androgens and estrogens in response to gonadotropin stimulation. Distinctive responses of 17-hydroxyprogesterone and androstenedione to ovarian stimulation testing suggest that ovarian hyperandrogenism is a result of dysregulation of theca cell androgen production which is intrinsic to the ovary. The occurrence of hyperestrogenism together with hyperandrogenism in PCOS suggests that whatever the abnormality of local regulatory factors of steroidogenesis, it affects granulosa as well as theca cells. Dysregulation is often associated with an increase in the number of follicles which evade atresia and reach the 2-8 mm stage of development. Autocrine/paracrine factors, especially those which are FSH-dependent, likely play an important role in the pathogenesis of the ovarian abnormality. Both LH and insulin hypersecretion probably play a secondary role in PCOS by amplifying the preexisting ovarian dysregulation. Because FSH secretion is under tight long-loop negative-feedback control and LH is not, hyperandrogenism is the primary clinical manifestation of dysregulation of steroid production in PCOS. However, anovulation in PCOS is most likely a result of excessive estrogen and inhibin production by multiple, small follicles which inhibit FSH secretory dynamics sufficiently to prevent selection of a dominant follicle.

Role of GnRH drive in the pathophysiology of polycystic ovary syndrome

Polycystic ovary syndrome may result from multiple mechanisms, but full expression of the PCO syndrome with hyperandrogenic anovulation depends upon sustained LH drive and relative FSH deficiency. We have described possible intrinsic and extrinsic factors capable of modifying the hypothalamic-pituitary-ovarian axis. Available evidence suggests the presence of an intrinsic alteration in GnRH-LH drive. The long-term natural history of HAA is variable and depends on several factors including obesity, aberrations in insulin action, intrinsic ovarian function, and end-organ responsiveness to androgens. Figure 1 presents a conceptualization of the pathogenesis of PCOS diagramming the multiple modulators of its expression. Long-term suppression of androgens when fertility is not desired should modify the full expression of the PCO syndrome. It is important to appreciate that therapy with oral contraceptive agents has few drawbacks and many immediate and potential long-term benefits for women with HAA. This therapy may be of greatest benefit when started in adolescence prior to the progression of obesity, hirsutism, and thecal-stromal hyperplasia. Women with HAA represent a large subgroup of patients who require individualization of their health care with sensitivity to issues surrounding anovulation, obesity, hirsutism, and infertility.

Effects of metformin on spontaneous and clomiphene-induced ovulation in the polycystic ovary syndrome

BACKGROUND

Obese women with the polycystic ovary syndrome are relatively unresponsive to the induction of ovulation by clomiphene. We hypothesized that reducing insulin secretion by administering metformin would increase the ovulatory response to clomiphene.

METHODS

We performed oral glucose-tolerance tests before and after the administration of 500 mg of metformin or placebo three times daily for 35 days in 61 obese women with the polycystic ovary syndrome. Women who did not ovulate spontaneously were then given 50 mg of clomiphene daily for five days while continuing to take metformin or placebo. Serum progesterone was measured on days 14, 28, 35, 44, and 53, and ovulation was presumed to have occurred if the concentration exceeded 8 ng per milliliter (26 nmol per liter) on any of these days.

RESULTS

Twenty-one women in the metformin group and 25 women in the placebo group were given clomiphene because they did not ovulate spontaneously during the first phase of the study. Among the 21 women given metformin plus clomiphene, the mean (+/-SE) area under the serum insulin curve after oral glucose administration decreased from 6745+/-2021 to 3479+/-455 microU per milliliter per minute (40.5+/-12.1 to 20.9+/-2.7 nmol per liter per minute, P=0.03), but it did not change significantly in the 25 women given placebo plus clomiphene. Nineteen of the 21 women (90 percent) who received metformin plus clomiphene ovulated (mean peak serum progesterone concentration, 23.8+/-3.4 ng per milliliter [7.6+/-10.9 nmol per liter]). Two of the 25 women (8 percent) who received placebo plus clomiphene ovulated (P<0.001). Overall, 31 of the 35 women (89 percent) treated with metformin ovulated spontaneously or in response to clomiphene, as compared with 3 of the 26 women (12 percent) treated with placebo.

CONCLUSIONS

The ovulatory response to clomiphene can be increased in obese women with the polycystic ovary syndrome by decreasing insulin secretion with metformin.

New approaches to insulin resistance in polycystic ovarian syndrome

The aetiology of the polycystic ovarian syndrome together with new advances in the molecular genetics and possible candidate genes for the inheritance of the syndrome is discussed. The possible role of leptin in the obesity of polycystic ovarian syndrome is reviewed. Hyperinsulinaemia acts not only as the trigger for hyperandrogenaemia and infertility, but also by stimulating plasminogen activator inhibitor type 1; hyperinsulinaemia may also promote atherogenesis in polycystic ovarian syndrome. The long-term effects of the metabolic derangements accompanying hyperinsulinaemia are reviewed. Special emphasis is placed on the use of novel insulin sensitizers such as troglitazone which promise new treatment opportunities in polycystic ovarian syndrome for both fertility and long-term disease prevention.

Human chorionic gonadotropin stimulation to assess for ovarian hyperandrogenism

STUDY OBJECTIVE

To determine whether human chorionic gonadotropin (hCG) stimulation elicits an exaggerated 17-hydroxyprogesterone (17-OHP) response in patients with functional ovarian hyperandrogenism.

METHODS

In this clinical study, healthy volunteers and hyperandrogenic patients in an outpatient General Clinical Research Center (GCRC) setting were studied. Five adolescent girls with functional ovarian hyperandrogenism were studied. Six healthy women with regular menstrual cycles volunteered for this study. Steroid hormone responses to hCG stimulation were measured before and 30, 240, and 300 minutes after hCG injection. Congenital adrenal hyperplasia was excluded through ACTH stimulation testing and molecular genetic analysis.

MAIN OUTCOME MEASURE

17-OHP responses.

RESULTS

Mean basal 17-OHP concentrations were greater in the hyperandrogenic patients, 110.4+/-41.2 ng/dL versus 61.8+/-28.6 ng/dL. After hCG stimulation, 17-hydroxyprogesterone concentrations significantly increased in the patients and were unchanged in the healthy controls.

CONCLUSION

hCG stimulation elicited greater 17-hydroxyprogesterone responses in adolescent girls with functional ovarian hyperandrogenism compared with healthy controls. hCG stimulation may be helpful to confirm ovarian hyperandrogenism.