Low levels of low molecular weight insulin-like growth factor-binding protein in patients with polycystic ovarian disease

Polycystic ovaries and levels of gonadotrophins and androgens in recurrent miscarriage: prospective study in 50 women

OBJECTIVE

To compare the serum levels of gonadotrophins and androgens, as well as ovarian morphology, in 50 women with a history of recurrent miscarriage and in 20 healthy controls.

DESIGN

Prospective study on women with a history of at least three consecutive miscarriages in Department I and II of Obstetrics and Gynecology, University Central Hospital of Helsinki, Finland.

RESULTS

The recurrent miscarriage group as a whole exhibited gonadotrophin and androgen levels comparable to those seen in the controls. Ultrasound examination revealed polycystic ovaries (PCO) in 22 patients (44%) and in four control women (20%, P = 0.06) but no differences in the levels of gonadotrophins and androgens emerged between the patients with or without PCO. During follow up, 33 (66%) women with a history of recurrent miscarriage who became pregnant; 16 miscarried again (48.5%), whereas 17 (51.5%) succeeded. The presence of PCO did not predict miscarriage, but the patients who miscarried had higher levels of total testosterone, free testosterone and dehydroepiandrosterone sulphate than RSA women with continuing pregnancies.

CONCLUSIONS

PCO and hyperandrogenism may be associated with repeated miscarriage.

Body weight, hyperinsulinemia, and gonadotropin levels in the polycystic ovarian syndrome: evidence of two distinct populations

OBJECTIVE

To investigate the impact of body weight (BW) and insulin levels on gonadotropin and androgen levels in women with the polycystic ovarian syndrome (PCOS).

DESIGN

Comparative study of endocrinologic parameters in PCOS women.

SETTING

University Hospital Reproductive Endocrinology Unit.

PATIENTS

Thirty obese and 19 nonobese women with PCOS. Seven obese and 7 nonobese normal women.

MAIN OUTCOME MEASURES

Serum concentrations of insulin, testosterone, androstenedione, luteinizing hormone (LH), follicle-stimulating hormone. Serum LH response to gonadotropin-releasing hormone (GnRH) administration and assessment of insulin resistance by the continuous infusion of glucose with model assessment (CIGMA) test.

RESULTS

Fasting insulin levels correlated with body mass index (BMI). Basal LH levels correlated inversely with BMI. Nonobese women with PCOS had a higher LH response to GnRH than obese women with PCOS. Only obese women with PCOS showed insulin resistance and fasting hyperinsulinemia.

CONCLUSIONS

The data suggest that women with PCOS may be divided into two subgroups: those with obesity, insulin resistance, hyperinsulinemia, and normal/minimally elevated LH levels and those with normal BW, elevated LH levels, and normoinsulinemia.

The effect of estrogen level on glucose-induced changes in serum insulin-like growth factor binding protein-1 concentration

OBJECTIVE

To investigate the regulation of insulin-like growth factor binding protein-1 (IGFBP-1) concentration during ovarian stimulation.

DESIGN

A prospective study of patients undergoing in vitro fertilization treatment.

SETTING

Infertility unit at the University Central Hospital of Oulu, a tertiary referral center.

PATIENTS

Sixteen healthy, regularly menstruating lean tubal infertility patients.

INTERVENTIONS

Oral glucose tolerance test was performed first in a hypoestrogenic state after suppression by long-term gonadotropin-releasing hormone (GnRH) agonist and, second, in a hyperestrogenic state after stimulation by human menopausal gonadotropins.

MAIN OUTCOME MEASURES

Serum concentrations of IGFBP-1, insulin-like growth factor I (IGF-I), insulin and sex hormone-binding globulin were measured before and 2 hours after glucose administration.

RESULTS

Before and after glucose administration, the serum IGFBP-1 concentrations were significantly higher in the hyperestrogenic state (estradiol [E2] level 3.5 +/- 0.57 nmol/L) after ovarian stimulation than in the GnRH-analogue-induced hypoestrogenic state before the gonadotropin treatment (E2 level 0.10 +/- 0.02 nmol/L). On both occasions glucose-induced hyperinsulinemia caused a significant decrease in the circulating IGFBP-1 levels, whereas the IGF-I levels remained unchanged. There was a significant correlation between E2 and the insulin-suppressed IGFBP-1 level. The sum of follicular diameters correlated positively with the serum IGFBP-1 concentration.

CONCLUSIONS

Gonadotropin-induced hyperestrogenism is related to elevated serum IGFBP-1 levels, either via estrogen-stimulated synthesis or via increased contribution from multiple follicles. Glucose-induced hyperinsulinemia suppresses serum IBFBP-1 concentration equally both in the hypoestrogenic and hyperestrogenic states. Because of similar IGF-I levels, it is likely that the biological activity of IGF-I is different before and after gonadotropin stimulations.

Insulin-like growth factor binding protein-1 in female reproductive functions

Multiple lines of evidence suggest that growth factors and related proteins are involved in the regulation of reproductive functions. It appears that hormones and local regulators control each other's production and action. Thus, the same regulatory factor may have different effects depending on the context in which it acts. Insulin-like growth factor-binding protein-1 (IGEBP-1) is a member of the family of soluble proteins that bind insulin-like growth factors (IGF-I and IGF-II) and modulate their biological actions at the cellular level. In the reproductive tract, endometrium and ovarian granulosa-luteal cells express IGFBP-1 mRNA and secrete the protein at a certain stage of differentiation. During pregnancy, IGFBP-1 is a major secretory product of decidualized endometrium. This report summarizes the current views on IGFBP-1 with special regard to its synthesis, regulation and potential role in female reproductive tissues.

Clinical features and circulating gonadotropin, insulin, and androgen interactions in women with polycystic ovarian disease

OBJECTIVE

To investigate the interactions of hyperinsulinemia and inappropriate gonadotropin secretion in women with polycystic ovarian disease (PCOD).

DESIGN

Comparative study of endocrinologic parameters in subjects with PCOD.

SETTING

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

PATIENTS

Fourteen nonobese and 10 obese patients with PCOD. Seven healthy women for reference data collection. Normal thyroid function, serum prolactin concentration, normal diurnal cortisol variation, euglycemia in all subjects.

MAIN OUTCOME MEASURES

Serum concentrations of insulin, testosterone, androstenedione, dehydroepiandrosterone sulfate, sex hormone-binding globulin, immunoreactive luteinizing hormone (LH), bioactive LH, and follicle-stimulating hormone (FSH).

RESULTS

The concentration of insulin was higher and that of bioactive LH was lower in obese than in nonobese PCOD women in whom the levels were also above the upper reference value. There was a negative correlation between insulin and bioactive LH levels (r = -0.57). Bioactive LH correlated inversely with the body mass index (BMI) (r = -0.50). After eliminating the effect of the BMI, the correlation between bioactive LH and insulin was no longer significant (r = -0.37). The bioactive LH and immunoreactive LH/FSH ratio correlated significantly (r = 0.68).

CONCLUSIONS

These data demonstrate that hyperandrogenic women can be divided into two subgroups: those with insulin resistance, normal or minimally elevated LH, and markedly elevated insulin levels; and those with elevated LH levels, no insulin resistance, and normal insulin concentrations. Obesity is associated with the former, and high bioactive LH levels with the latter subgroup.

Interactions between insulin and insulin-like growth factor I in the pathogenesis of polycystic ovarian disease

Concentrations of growth factors were examined in 28 patients with clinical and endocrinologic signs of polycystic ovarian disease (PCOD). Elevated levels of total insulin-like growth factor I (IGF-I) and decreased levels of the human growth hormone (HGH) were found. Studies of carbohydrate metabolism and of insulin receptors on erythrocytes indicated insulin resistance in all PCOD patients. Elevated insulin and IGF-I levels seem to play a pathogenetic role in PCOD by influencing the development and steroid production of ovarian follicles. Interactions between insulin and IGF-I could be shown at different levels. A positive correlation between elevated insulin and IGF-I concentrations was demonstrated in patients with different classes of gestational diabetes. Hyperinsulinemia seems to be the trigger mechanism and therefore the key to the pathogenetic loop of polycystic ovarian disease.

Obesity and polycystic ovary syndrome

Our studies show that obese women with polycystic ovary syndrome are more likely to have hirsutism and menstrual disturbances than are lean women with PCOS. The most obvious biochemical differences between obese and lean women with PCOS is that SHBG concentrations are much lower in women with obesity. The SHBG levels are inversely related to insulin, and insulin has been shown to have a direct inhibitory action on SHBG secretion. Other factors, however, may contribute to the mechanism of the increased prevalence of hirsutism and anovulation in obese women with PCOS, such as a direct effect of insulin or increased activity of 5 alpha-reductase in peripheral tissues. Finally we have been able to show that weight reduction of more than 5% is associated with an improved biochemical profile and, importantly, with restoration of fertility.

Oral contraceptives increase insulin-like growth factor binding protein-1 concentration in women with polycystic ovarian disease

Insulin-like growth factor-I (IGF-I) stimulates ovarian androgen production. Insulin-like growth factor binding protein-1 (IGFBP-1) inhibits IGF actions in vitro.

OBJECTIVE

To investigate the effect of oral contraceptive (OC) pills, given for 3 months, on serum gonadotropin, androgen, IGF-I, and IGFBP-1 concentrations, and glucose tolerance in seven women with polycystic ovarian disease (PCOD) and in five healthy control subjects.

PATIENTS

Seven women with PCOD and five healthy control subjects.

INTERVENTIONS

An oral glucose tolerance test (OGTT) was performed before and after treatment with OC.

RESULTS

After treatment with OC, serum luteinizing hormone, androstenedione, and free testosterone levels decreased, and sex hormone-binding globulin concentration increased in the women with PCOD as well as in the control subjects. The cumulative response of serum insulin to OGTT was larger in the women with PCOD than in the control subjects both before and after treatment. Serum IGF-I concentration, which was unchanged during OGTT, decreased from basal level of 326 +/- 70 micrograms/L to 199 +/- 28 micrograms/L after treatment with OC in the women with PCOD, whereas no change was found in the control subjects (from 235 +/- 11 micrograms/L to 226 +/- 11 micrograms/L). Treatment with OC caused an increase of the mean basal IGFBP-1 concentration from 24 +/- 7 micrograms/L to 73 +/- 14 micrograms/L in the women with PCOD. This increase was constant during the OGTT. In the control subjects, treatment with OC did not result in any significant change in IGFBP-1 concentrations (from 44 +/- 11 micrograms/L to 61 +/- 9 micrograms/L).

CONCLUSION

The combination of decreased total IGF-I concentration and increased IGFBP-1 concentration induced by OC may decrease ovarian androgen production in PCOD.

Inter-relations between growth hormone, insulin, insulin-like growth factor-I (IGF-I), IGF-binding protein-1 (IGFBP-1) and sex hormone-binding globulin in acromegaly

Acromegaly is characterized by a hypersecretion of GH, which in turn results in an excess of IGF-I, an important mediator of its actions. IGF-I itself is intimately related to insulin both in structure and function. IGF-I circulates associated with specific binding proteins which appear to have important effects on its activity. We have examined the inter-relations between GH, prolactin, insulin, IGF-I and one of the binding proteins, IGFBP-1, in 62 patients with acromegaly of varying activity. Serum IGF-I levels were closely related to the logarithm of mean GH levels (r = 0.76; n = 62; P less than 0.001) but multiple regression analysis suggested that, after accounting for the variation due to GH, insulin accounted for some of the additional variation of IGF-I. IGF-I concentrations were independent of prolactin. Fasting insulin levels were high and unrelated to mean GH levels but correlated with those of IGF-I (r = 0.542; n = 57; P less than 0.001). This correlation coefficient was further improved by also accounting for variations in IGFBP-1 (r = 0.684; n = 57; P less than 0.001). Even in subjects whose acromegaly was well controlled or cured, as indicated by GH levels of less than 1 mU/l or IGF-I levels of less than 2 U/ml, fasting insulin levels remained significantly elevated in some individuals. The reason for this persistent abnormality is not clear. Fasting IGFBP-1 levels were low and unrelated to mean GH but were inversely related to fasting insulin levels (r = -0.593; n = 57; P less than 0.001). We propose that a cascade of events occurs in acromegaly.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of luteinizing hormone, insulin, insulin-like growth factor-I and insulin-like growth factor small binding protein 1 in the polycystic ovary syndrome

This study explores the clinical and endocrine implications of hyperinsulinaemia in the polycystic ovary syndrome (PCOS). Oral glucose tolerance tests were performed on 34 lean and 19 obese women with PCOS and on 13 lean women with normal ovaries. Insulin measurements were compared with basal gonadotrophins, androgens, insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein 1 (IGFBP-1). Unselected lean women with PCOS were found to have fasting hyperinsulinaemia and the raised serum insulin concentrations were associated with menstrual disturbance and hyperandrogenaemia. In addition, serum insulin concentrations in lean women with PCOS correlated positively with serum IGF-I and negatively with serum IGFBP-1 concentrations. Ovarian stimulation by insulin appears to be independent of luteinizing hormone (LH) and is an important feature in 30% of lean women with PCOS.

Accidental hyperstimulation during ovulation induction

Clinical hyperstimulation is the most serious complication of ovulation induction, occurring in approximately 3% of cases (0.8% in the severe form). Paradoxically, it seems to be rare following in vitro fertilization, probably because all the follicles are aspirated. High-risk patients are those with polycystic ovarian disease, hyperprolactinaemia and hypothyroidism. All forms of ovulation induction have been implicated. Use of LHRH agonists have not reduced the incidence of hyperstimulation and they may even have increased it. An ongoing pregnancy seems to predispose to the occurrence of hyperstimulation, due to the secretion of hCG. Clinically, three stages of hyperstimulation have been described by the WHO (mild, moderate and severe). The pathophysiology is not completely understood, although prostaglandins, histamines and, especially, the ovarian renin-angiotensin system may be involved. Local ovarian complications and thromboembolic complications have also occurred. The treatment of severe hyperstimulation is both symptomatic (fluid replacement, aspiration of effusions, moderate sodium and water restriction, small doses of diuretics) and specific (corticosteroids, aspiration of ovarian cysts, even voluntary interruption of pregnancy in the most serious forms). If the hyperstimulation occurs in the absence of pregnancy, antihistamines or antiprostaglandins can be given. Prevention is exceedingly important. This can be helped by recognition of polycystic ovarian disease and stimulation of these cases by clomiphene citrate or pure FSH associated, for use in in vitro fertilization, with prolonged desensitization using LHRH agonists. Daily ultrasound and hormonal monitoring of ovulation induction is required. When there is excessive response to stimulation, it is prudent not to induce ovulation with hCG or, alternatively, to aspirate all the follicles and freeze the embryos obtained without giving further injections of hCG in the luteal phase. Clinical ovarian hyperstimulation is the classic form of iatrogenic disorder and is the most important complication of ovulation induction treatments, since it can be life-threatening in its most severe form. In this chapter we review current knowledge concerning the frequency, factors associated with its occurrence, clinical aspects, physiopathological mechanisms and, finally, the possibilities for treatment and prevention.

Effect of naloxone on plasma insulin, insulin-like growth factor I, and its binding protein 1 in patients with polycystic ovarian disease

Insulin and insulin-like growth factors (IGFs) stimulate ovarian steroidogenesis, and hyperinsulinemia is often accompanied by hyperandrogenemia in women with polycystic ovarian disease (PCOD). Because opioid peptides are involved in the regulation of insulin secretion, we studied the effect of naloxone-induced opiate receptor blockade on the circulating levels of insulin, IGF-I, and IGF binding protein 1 (IGFBP-1) in 13 nonobese and 7 obese PCOD patients and in 6 healthy subjects. In obese PCOD patients, the mean basal insulin concentration was significantly higher and the IGFBP-1 concentration lower than in nonobese PCOD patients. Plasma IGF-I levels were elevated both in obese and nonobese PCOD patients. After an intravenous bolus of 10 mg naloxone, no significant changes were found in the circulating insulin or IGF-I levels, whereas IGFBP-1 levels decreased in nonobese PCOD patients and remained low in obese PCOD patients. No significant decrease was found in healthy subjects. These results suggest that, in addition to insulin, endogenous opioids are involved in the regulation of serum IGFBP-1 level.

Hirsutism: definitions and etiology

Hirsutism as a sign of hyperandrogenism is a common endocrinological disorder in women. Its spectrum varies from mild forms with dominating psychic component to severe forms associated with virilization. The severity should be assessed by semiobjective scoring systems, the use of which also allows the systematic follow-up of the results of treatment. An increase in serum androgen levels or an increased turnover of androgens can be detected in most patients. Enhanced peripheral conversion of androgens to locally acting androgen also leads to hirsutism. The thorough investigation of the endocrinological milieu is required to rule out androgen producing neoplasms. In most patient, however, disturbances are functional, among which polycystic ovary syndrome is the commonest. It is a disorder exhibiting a complexity of changes in endocrinological interactions. Besides inappropriate gonadotropin secretion insulin and insulin like growth factor are also involved. The opioidergic system also seems to be affected. Polycystic ovary syndrome is also associated with obesity and infertility, both of which require attention.

Diet-induced changes in sex hormone binding globulin and free testosterone in women with normal or polycystic ovaries: correlation with serum insulin and insulin-like growth factor-I

The purpose of this study was to investigate the effect of calorie restriction on serum concentrations of sex hormone binding globulin (SHBG) in women with normal or polycystic ovaries (PCO) and to examine the possible role of insulin and insulin-like growth factor-I (IGF-I) in mediating changes in SHBG levels. Six normal subjects with mean (SD) body mass index (BMI) 25.5 (2.2) and five subjects with PCO (BMI 36.1 (3.7)) were studied before and after 2 or (PCO only) 4 weeks of a very low calorie diet (330 kcal/day; Cambridge Diet). In both normal women and patients with PCO there was a twofold increase in SHBG concentrations after 2 weeks and this was sustained in the PCO subjects for a further 2 weeks. The rise in SHBG was accompanied by a fall in free testosterone concentrations. There were parallel changes in serum insulin and IGF-I concentrations which decreased during the diet and there were significant negative correlations of SHBG with insulin in both normal subjects (r = -0.62) and women with PCO (r = -0.60). In addition, serum concentrations of an insulin-dependent small molecular weight (34 kDa) binding protein for IGF-I (IGF-BPI) increased significantly during dieting in both groups and were negatively correlated with serum insulin (controls, r = -0.56; PCO, r = -0.68) and positively correlated with serum SHBG levels (controls, r = 0.69; PCO, r = 0.63). In summary, these data indicate that in both normal subjects and those subjects with PCO, calorie restriction results in a highly significant increase in SHBG concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)