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

Association of Insulin-Like Growth Factor-1 With Polycystic Ovarian Syndrome: A Systematic Review and Meta-analysis

OBJECTIVE

Circulating concentration of insulin-like growth factor (IGF)-1 in patients with polycystic ovary syndrome (PCOS) is still unclear. Therefore, we aimed to investigate the association of IGF-1 with PCOS through this meta-analysis.

METHODS

Literature search was conducted through PubMed, Embase, Web of Science, Cochrane Library, and China National Knowledge Infrastructure (up to July 2022). A manual search was performed on the references of related original research. Then, we applied the random-effects model to evaluate the overall effect size by calculating the standard mean difference and its 95% CI. Subgroup analyses were used to explore the sources of heterogeneity. In addition, a sensitivity analysis was performed and publication bias was assessed.

RESULTS

Twenty studies were included in this meta-analysis involving 657 individuals: 362 patients with PCOS and 295 normal controls. The results of meta-analysis showed that serum IGF-1 levels were significantly higher in patients with PCOS than in controls (standard mean difference, 0.89; 95% CI, 0.34-1.45; P = .002). The final pooled data were determined by the random-effects model because a significant high heterogeneity (I² = 89%) was found. A subgroup analysis based on body mass index showed that elevated IGF-1 level was associated with normal-weight and overweight patients in the PCOS group, but there was no significant association with obesity. The sensitivity analysis indicated that no individual study significantly affected the overall pooled result and no publishing bias was observed.

CONCLUSION

These data suggest that elevated serum IGF-1 levels may not be a major cause of PCOS pathogenesis. Body mass index may be a major determinant of serum IGF-1.

Effects of Oral Contraception and Lifestyle Modification on Incretins and TGF-ß Superfamily Hormones in PCOS

OBJECTIVE

To examine the effects of common treatments for polycystic ovary syndrome (PCOS) on a panel of hormones (reproductive/metabolic).

DESIGN

Secondary analysis of blood from a randomized controlled trial of three 16-week preconception interventions designed to improve PCOS-related abnormalities: continuous oral contraceptive pills (OCPs, N = 34 subjects), intensive lifestyle modification (Lifestyle, N = 31), or a combination of both (Combined, N = 29).

MATERIALS AND METHODS

Post-treatment levels of activin A and B, inhibin B, and follistatin (FST), as well as Insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein 2 (IGFBP-2), glucagon, glucagon-like peptide 1 (GLP-1) and 2, and oxyntomodulin were compared to baseline, and the change from baseline in these parameters were correlated with outcomes.

RESULTS

Oral contraceptive pill use was associated with a significant suppression in activin A, inhibin A, and anti-mullerian hormone (AMH), but a significant increase in FST. IGF-1, IGFBP-2, glucagon, and GLP-2 levels were significantly decreased. Oxyntomodulin was profoundly suppressed by OCPs (ratio of geometric means: 0.09, 95% confidence interval [CI]: 0.05, 0.18, P < 0.001). None of the analytes were significantly affected by Lifestyle, whereas the effects of Combined were similar to OCPs alone, although attenuated. Oxyntomodulin was significantly positively associated with the change in total ovarian volume (rs = 0.27; 95% CI: 0.03, 0.48; P = 0.03) and insulin sensitivity index (rs = 0.48; 95% CI: 0.27, 0.64; P < 0.001), and it was inversely correlated with change in area under the curve (AUC) glucose [rs = -0.38; 95% CI: -0.57, -0.16; P = 0.001]. None of the hormonal changes were associated with live birth, only Activin A was associated with ovulation (risk ratio per 1 ng/mL increase in change in Activin A: 6.0 [2.2, 16.2]; P < 0.001).

CONCLUSIONS

In women with PCOS, OCPs (and not Lifestyle) affect a wide variety of reproductive/metabolic hormones, but their treatment response does not correlate with live birth.

The effect of cinnamon on polycystic ovary syndrome in a mouse model

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most prevalent cause of anovulatory infertility and hyperandrogenism. Evidence favors insulin resistance and compensatory hyperinsulinemia as the predominant, perhaps primary, defects in PCOS. The use of insulin-sensitizing drugs has been shown to improve both the reproductive and the metabolic aspects of PCOS. Cinnamon has been found to have insulin sensitizing effect and improve menstrual cyclicity in women with PCOS. The aim of this study was to determine the effect and mechanism of cinnamon on PCOS using a dehydroepiandrosterone (DHEA) induced PCOS mouse model.

METHODS

Prepubertal C57BL/6 mice (age 25 days) were raised to developed into control group, DHEA group and DHEA plus cinnamon group for 20 days. The stages of the estrous cycle were determined based on vaginal cytology; metabolic characteristics were examined by intraperitoneal glucose tolerance test and insulin tolerance test, the serum levels of hormones (testosterone, insulin, LH, FSH, IGF-1, IGFBP-1) were checked using enzyme-linked immunosorbent assay (ELISA) method, the ovarian morphology was observed by stained with hematoxylin and eosin. IGF-1 and IGFBP-1 expression in ovary were detected by immunohistochemical stain.

RESULTS

Cinnamon restores the cyclicity and ovary morphology in PCOS mice model induced by DHEA. There are significant differences of serum level of total testosterone (0.033 ± 0.009 ng/ml), among control group, DHEA and cinnamon group (0.052 ± 0.011 ng/ml), and DHEA group (0.079 ± 0.015 ng/ml); There was an increasing tendency of serum FSH level from DHEA group (5.02 ± 0.31 ng/ml), DHEA and cinnamon group (5.81 ± 0.51 ng/ml), to control group (7.13 ± 0.74 ng/ml); and there was a decreasing trend of serum LH level from DHEA group (3.75 ± 0.57 ng/ml), DHEA and cinnamon group (1.35 ± 0.61 ng/ml), or control group (0.69 ± 0.34 ng/ml); serum insulin level is significantly higher in DHEA treated mice (1.61 ± 0.31 ng/ml) than control group (0.93 ± 0.19 ng/ml), or DHEA and cinnamon effect (1.27 ± 0.23 ng/ml) (p < 0.05). The DHEA group also has a higher serum IGF-1 level (0.35 ± 0.06 ng/ml) than control group (0.17 ± 0.04 ng/ml) or DHEA and cinnamon group (0.21 ± 0.05 ng/ml) (p < 0.05). While DHEA group has a lower IGFBP-1 level (5.5 ± 1.6 ng/ml) than control group (15.8 ± 2.1 ng/ml) or DHEA and cinnamon group (10.3 ± 2.5 ng/ml) (p < 0.05). Cinnamon also attenuates DHEA induced a higher IGF-1 and lower IGFBP-1 expression in ovary by immunohistochemistry.

CONCLUSIONS

These preliminary data suggest that cinnamon supplementation improves insulin resistance and may be a potential therapeutic agent for the treatment of PCOS.

Association of circulating insulin-like growth factor 1 and insulin-like growth factor binding protein 3 with the risk of ovarian cancer: A systematic review and meta-analysis

Insulin-like growth factor 1 (IGF-1) and its main binding protein (IGFBP-3) in blood have been associated with the risk of several types of cancer. However, epidemiological studies have inconsistent results regarding the association of circulating IGF-1/IGFBP-3 levels with ovarian cancer risk. A systematic review of the prospective studies was conducted using meta-analysis to evaluate the existing evidence. Pubmed and Embase databases were searched to identify the relevant studies published before May 1, 2014. Four highly qualified studies with a total of 627 cases and 1,358 controls were finally included in the meta-analysis. Random effects meta-analysis was conducted by combining study-specific odds ratios (ORs) of ovarian cancer for the highest verses lowest exposure levels. A dose-response association was further assessed by relating the log of ORs for different exposure levels. As a result, the pooled ORs for the highest verses lowest categories of IGF-1/IGFBP-3 were 0.85 [95% confidence interval (CI), 0.51-1.40]/0.78 (95% CI, 0.43-1.40). In the subgroup analyses, the pooled ORs of IGF-1/IGFBP-3 were 1.89 (95% CI, 0.64-5.59)/1.08 (95% CI, 0.50-2.32) for the subgroup with cases diagnosed at <55 years, and 0.74 (95% CI, 0.50-1.08)/0.98 (95% CI, 0.73-1.33) for the subgroup with cases diagnosed at ≥55 years. No linear association between circulating IGF-1/IGFBP-3 levels and ovarian cancer risk was identified. As no significant association of IGF-1/IGFBP-3 with ovarian cancer risk was identified in the present meta-analysis of existing studies, more studies with greater quality are required in the future.

Estrogen and selective estrogen receptor modulators (SERMs) for the treatment of acromegaly: a meta-analysis of published observational studies

Estrogen and selective estrogen receptor modulator (SERM) treatments for acromegaly have received limited attention since the development of newer pharmacologic therapies. There has been ongoing research evidence suggesting their utility in the biochemical control of acromegaly. Therefore, the aim of this meta-analysis was to synthesise current evidence with a view to determining to what extent and in which acromegalic patient subsets do estrogen and SERMs reduce IGF-1 levels. A literature search was conducted (finished December 2012), which included all studies pertaining to estrogen or SERM treatment and IGF-1. Seven patient subsets were identified from six published observational studies, and were pooled using meta-analytic methods. Overall, the pooled mean loss in IGF-1 was -29.09 nmol/L (95 % CI -37.23 to -20.95). A sensitivity analysis indicated that women receiving estrogen had a substantially greater reduction in IGF-1 levels compared with women receiving SERMs, with a weighted mean loss in IGF-1 of -38.12 nmol/L (95 % CI -46.78 to -29.45) compared with -22.91 nmol/L (95 % CI -32.73 to -13.09). There was a trend that did not reach statistical significance for men receiving SERM treatment at -11.41 nmol/L (95 % CI -30.14 to 7.31). It was concluded that estrogen and SERMs are a low cost and effective treatment to achieve control of IGF-1 levels in acromegalic women either as concomitant treatment for refractory disease, or where access to conventional therapy is restricted. Their use in men requires further study.

IGF-binding protein 1 and abdominal obesity in the development of type 2 diabetes in women

OBJECTIVE

Low levels of IGF-binding protein 1 (IGFBP1) are associated with metabolic syndrome and predict diabetes development in men. The aim of this study was to determine the levels of IGFBP1 in women who later develop diabetes, in relation to abdominal obesity, and to compare these levels with those of men.

METHODS

IGFBP1 levels were determined at baseline and after 8 years in a case-control, prospective study of Swedish women aged 35-56 years. Individuals with normal oral glucose tolerance test (OGTT) who developed abnormal glucose regulation (n=240) were pair matched to controls for age and family history of diabetes and also compared to men of the same age (n=355).

RESULTS

Low fasting IGFBP1 and increased waist measurement predicted development of diabetes in women (n=60; odds ratio (OR) 70, 95% confidence interval (CI) 8-661, lowest tertile and OR 27, 95% CI 5-141, highest tertile). In women developing diabetes, baseline IGFBP1 levels were lower than expected for fasting insulin values, were associated with impaired suppression after OGTT and increased during 8 years despite an increase in fasting insulin. All individuals in the highest tertile for waist and with <or=40% suppression of IGFBP1 developed diabetes within 8 years. Circulating IGFBP1 concentrations were higher in women compared to men. Women and men who developed diabetes had a similar degree of abdominal obesity, corrected for height.

CONCLUSIONS

We conclude that low IGFBP1 and elevated waist measurement predict diabetes development and that IGFBP1 production is suppressed by a novel factor(s) in women developing diabetes. Increasing levels of IGFBP1 during the emergence of diabetes in men and women suggest the emergence of hepatic insulin resistance.

Insulin-like growth factor binding protein-1 in PCOS: a systematic review and meta-analysis

BACKGROUND

Despite extensive research, the pathogenesis of polycystic ovary syndrome (PCOS) remains unclear. Putatively, an elevated circulating concentration of insulin inhibits the production of insulin-like growth factor binding protein-1 (IGFBP-1), thus increasing the level of free IGF-I in serum and stimulating ovarian androgen production. Decreased IGFBP-1 has been reported in PCOS and in obesity; however, there are inconsistencies in the evidence. This systematic review and meta-analysis aimed to determine whether IGFBP-1 is decreased in PCOS when controlling for the influence of BMI.

METHODS

Articles published between 1988 and 2008 were searched using MEDLINE, PubMed, SCOPUS and Web of Knowledge. Unpublished literature, trials in progress, and recent reviews were also searched. Original articles were selected by two investigators. To be included, the study must have compared serum IGFBP-1 in two populations: either PCOS versus controls, or an overweight subgroup versus the normal weight subgroup in either population. From 617 identified articles, 12 were included in the meta-analysis. Data were abstracted by two reviewers independently and standardized for errors.

RESULTS

The population difference is presented as the Weighted Mean Difference (95% CI). PCOS subjects had a significantly lower serum concentrations of IGFBP-1 compared with controls [P< 0.00001; -36.6 (-52.0, -21.2) µg/l]. Overweight PCOS subjects also had lower IGFBP-1 levels compared with normal weight PCOS subjects [P < 0.006; -30.6 (-52.3, -8.8) µg/l]. No significant difference was found between overweight PCOS patients and overweight controls [P = 0.23; -5.1 (-13.5, 3.2) µg/l] or between normal weight PCOS patients and normal weight controls [P = 0.50; -3.8 (-14.9, 7.3) µg/l]. Overweight controls had significantly lower IGFBP-1 concentrations than normal weight controls [P = 0.03; -18.0 (-34.4, - 1.5) µg/l].

CONCLUSION

These data indicate that a decreased serum level of IGFBP-1 is unlikely to be a mechanism for ovarian hyperandrogenism in PCOS. BMI may be the major determinant of serum IGFBP-1.

Efficacy of combined ethinyloestradiol (0.035 mg) and cyproterone acetate (2 mg) in acne and hirsutism in women with polycystic ovary syndrome

The effects of an oral contraceptive containing ethinyloestradiol and cyproterone acetate on acne and hirsutism were studied in 82 women with polycystic ovary syndrome. The contraceptive was administered for 48 consecutive cycles. Hormone and ultrasound evaluations were carried out at baseline and after 48 treatment cycles. Acne and hirsutism were evaluated after 18, 24, 36 and 48 treatment cycles. Acne resolved in all patients within 24 treatment cycles. Mild and moderate hirsutism resolved within 48 treatment cycles. Severe hirsutism persisted although it changed to mild or moderate in most of the affected women.

Influence of pituitary suppression with triphasic or monophasic oral contraceptives on the outcome of in vitro fertilization and embryo transfer

PURPOSE

To compare the clinical outcome of IVF treatment after pituitary suppression with two different oral contraceptives (OCs).

METHODS

65 patients who received IVF treatment was classified into 2 groups based on the difference of OCs they used for pituitary suppression before ovarian hyperstimulation. Group 1 included 36 patients who received monophasic OCs. Group 2 included 29 patients who received triphastic OCs. Both groups received the OCs from the 5th day of the cycle for consecutive 21 days. The hormone profiles after OCs and clinical outcome of IVF treatment were compared between two groups. Two-sample t-tests and X2 tests were used for statistical analyses. P < 0.05 was considered statistically significant.

RESULTS

The mean age and basal hormone profiles were comparable between two groups. After ovulation suppression with different OCs, the day 2 FSH and LH value revealed statistically significant difference between two groups(4.2+/-1.8 vs 6.0+/-2.6; 2.7+/-2.0 vs 4.2+/-3.3 respectively). The numbers of oocyte per retrieval and fertilization rate were comparable between two groups, but higher quality embryos as revealed by the cleavage speed were noted in the triphastic OCs group. Although statistically not significant, higher implantation rate and pregnancy rate were also noted in the triphastic OCs group.

CONCLUSIONS

Different OCs for pituitary suppression can result in different hormone profiles. Ovulation induction in IVF treatment should be individualized according to these hormone changes to achieve the optimal clinical outcome. Triphastic OCs exceeds monophastic OCs in producing good quality embryo in IVF-ET treatment.

[Polycystic ovary syndrome: recent genetic contributions]

Polycystic ovary syndrome is the most common endocrine disorder in women of reproductive age. It is characterized by hyperandrogenism, chronic anovulation and it is often associated with hyperinsulinemia, insulin resistance and dyslipidaemia. The pathophysiology of polycystic ovary syndrome seems to implicate primary defects in ovarian steroidogenesis, influenced by environment, insulin action and obesity. Polycystic ovary syndrome is probably both a multigenetic and environmental disease. Knowing the genes of polycystic ovary syndrome would be helpful to develop therapeutics and prevention. Genes of gonadotrophins, steroid hormone synthesis and insulin resistance seem not to be directly involved, except perhaps the CYP 11 a gene. On the other hand, identification of the signal transduction pathways involved in these genes may provide valuable information that can be applied to other clinical manifestations of polycystic ovary syndrome (follicular growth arrest, insulin resistance, obesity and endometrial cancer...).

IGF-1 in gynaecology and obstetrics: update 2002

Recent discoveries on endocrine, paracrine and autocrine involvement of insulin-like growth factor-1 (IGF-1) in the proliferation of many tissues raised the attention of its role in reproduction and in the growth of various cancers as well as of benign proliferations. The intention of this article is to focus on IGF-1 in the field of gynaecology. Perimenopausal women who exhibit high IGF-1 and low IGF binding protein (IGFBP) levels, like IGFBG-3, have an increased risk of developing breast cancer. A higher risk for cervical, ovarian and endometrial cancer is related to high IGF-1 levels in post- and premenopausal women. It has been shown that myomas, by far the most common benign uterine tumor in women, grow in the presence of IGF-1, in vitro as well as in vivo. Studies show that IGF-1 is involved in the differentiation of various reproductive tissues, like endometrium and ovarian tissues. Patients suffering from polycystic ovary syndrome (PCO) frequently show insulin resistance accompanied by an increase of IGF-1 in plasma. Plasma IGF-1 levels are higher in cases of severe endometriosis, however, in endometriosis and in PCO IGF levels locally in the endometrium are reduced, what might explain infertility. Recently, it was shown that IGF facilitates the implantation of the human embryo in the endometrium during IVF. Implantation is a paradox where different immune systems have to collaborate to make implantation and survival of the pregnancy possible. IGF seems to be the starter molecule so that the two epithelia can fuse. A disturbance can result in complications during pregnancy i.e. spontaneous miscarriage, preeclampsia as well as defects of the embryo. Therefore, IGF is a useful marker in successful pregnancy as well. A better mechanistic understanding of IGF-1 action on the cellular level not only provides more elegant mechanistic explanations for the scientist, but the practitioner might find it interesting to utilize its diagnostic potential as a marker for various diseases. The relation between systemic IGF levels and local tissue IGF-1 levels has not yet been determined for all conditions.

Altered gene expression profile in chemically induced rat mammary adenocarcinomas and its modulation by an aromatase inhibitor

In the present study, competitive cDNA library screening (CCLS) and cDNA microarray analyses were employed to identify differentially expressed genes in methylnitrosourea-induced rat mammary adenocarcinomas. The preliminary screening of 100 000 plaques by CCLS identified 1217 clones with differential expression. Dot-blot analysis of the isolated clones verified differential expression in 471 distinct genes. Confirmation of these 471 genes was conducted by performing reverse transcription-polymerase chain reactions, and a total of 160 genes were confirmed after comparing six rat mammary adenocarcinomas and three normal rat mammary glands. Fifty-nine of these showed lower expression in the adenocarcinomas while the remaining 101 were overexpressed in the tumors. Employing a cDNA microarray containing 588 known genes revealed an additional 33 differentially expressed genes in these tumors. Importantly, most of the identified genes demonstrated relatively reproducible overexpression or underexpression in individual tumors. Many of the altered genes determined by cDNA microarray analysis were oncogenes, tumor suppressor genes, or genes involved in cell cycle control and apoptosis. CCLS identified many others not previously associated with mammary carcinogenesis, including a novel gene named RMT-7. Preliminary studies to determine the applicability of this gene expression approach for detecting potential biomarkers for cancer chemoprevention was evaluated in rat mammary tumors obtained from animals treated with vorozole, a potent aromatase inhibitor. When genes exhibiting differential expression as determined by CCLS or cDNA microarray analysis were examined in control and vorozole-treated tumors, expression of 19 genes was found to be modulated significantly in tumors treated with vorozole. Further investigations into these identified genes should contribute significantly to our understanding of the molecular mechanisms of rat mammary tumorigenesis. In addition, the identified genes may become useful targets for drug development and potential biomarkers for monitoring treatment and prevention of breast cancer in humans.

The insulin-like growth factor-I system and hormone replacement therapy

OBJECTIVE

To determine the effects of hormone replacement therapy on plasma concentrations of free and total insulin-like growth factor (IGF)-I, IGF binding protein (BP)-1, and IGFBP-3.

DESIGN

Clinical study.

SETTING

Gynecologic clinic at a university hospital.

PATIENT(S)

Seventy-one postmenopausal women.

INTERVENTION(S)

Six cycles of four different hormonal replacement therapy regimens: oral conjugated estrogens, transdermal estradiol, oral conjugated estrogens and norethisterone, and transdermal estradiol and norethisterone acetate.

MAIN OUTCOME MEASURE(S)

Blood samples were collected before and after treatment for measurement of free and total IGF-I, IGFBP-1, and IGFBP-3.

RESULT(S)

Conjugated estrogen replacement therapy is associated with a decrease in plasma concentration of total IGF-I and increase in concentrations of free IGF-I and IGFBP-1. Transdermal estrogens have no effect on total and free IGF-I and IGFBP-1 concentrations. Oral norethisterone plus conjugated estrogens increased free IGF-I and IGFBP-1 concentrations but did not change IGF-I concentrations. Transdermal conjugated estrogens plus norethisterone acetate increased free IGF-I concentrations but not total IGF-I or IGFBP-1 concentrations. The plasma concentration of IGFBP-3 did not change in any group.

CONCLUSION(S)

Alterations in total IGF-I concentration can occur depending on the route of hormone replacement therapy administration. Free IGF-I concentrations were elevated in all study groups except that treated with transdermal estrogens.

Management of hirsutism

This review reports our own experience with, and literature studies of, the pharmacological management of hirsutism in women with hyperandrogenism (polycystic ovary syndrome) or with normal serum androgen levels and regular ovulatory menstrual cycles (idiopathic hirsutism). Treatment consists of suppressing ovarian or adrenal androgen secretion, or blocking androgen actions in the skin. The major drugs used are gonadotropin-releasing hormone (GnRH) agonists, combined oral contraceptives (COCs), and steroidal (cyproterone acetate and spironolactone) or nonsteroidal (flutamide and finasteride) antiandrogens. GnRH agonists, suppressing the pituitary, decrease androgen and estradiol secretion and improve severe hirsutism. To avoid estrogen deficiency problems, 'add back' therapy with estrogen-progestogen or COCs is advisable. This method of treatment is complicated and expensive, limiting its use to severe forms of ovarian hyperandrogenism with hyperinsulinemia. The third-generation COCs, containing new progestogens or cyproterone, have very restricted effectiveness in the short term (6 cycles), but their long term use (> 12 cycles) cures mild-to-moderate hirsutism and improves severe hirsutism. As well as suppressing gonadotropins and ovarian androgen steroidogenesis, these formulations decrease free testosterone levels and may also decrease adrenal androgen production. In women being treated with antiandrogens, COCs are important to provide control of the menstrual cycle and contraception. Cyproterone, a progestational agent, inhibits gonadotropin secretion and blocks androgen action. It is used in COCs or in a reverse sequential regimen. In the latter, it is very effective in the short term treatment of hirsutism. Spironolactone blocks androgen receptors. Its effectiveness in hirsutism is dosage-dependent: low dosages are less active than other antiandrogens, whereas high dosages (200 mg/day) are very effective at the cost of several adverse effects (particularly dysfunctional uterine bleeding), but the concomitant use of a COC may prevent these. Flutamide is a pure antiandrogen that blocks androgen receptors and inhibits hair growth. It is very effective in treating hirsutism within 6 to 12 months. Dry skin is very frequent during treatment with flutamide, and hepatotoxicity is possible at high dosages. Finasteride, a 5 alpha-reductase type 2 inhibitor, is the least effective antiandrogen, but a dosage of 5 mg/day decreases hirsutism without adverse effects. Pregnancy must be avoided during therapy with antiandrogens because of the possible risk of abnormal development of a male fetus. Antiandrogens, especially flutamide (250 to 500 mg/day) and cyproterone (12.5 to 50 mg/day in a reverse sequential regimen), alone or in association with COCs, seem to be the most effective agents for the treatment of hirsutism.

GH, IGFBP-1, and IGFBP-3 response to oral glucose tolerance test in perimenopausal women: no influence of body mass index

OBJECTIVES

an increasing interest is being focused on the role of the somatotropic axis in the modulation of body weight and fat distribution, particularly in climacteric women. The influence of the glycometabolic state on the somatotropic axis in postmenopausal and in obese subjects has not been investigated. The aim of the present study is to evaluate whether menopause and body mass index (BMI) affect the response of growth hormone (GH), insulin-like growth factor-binding protein-1 (IGFBP-1) and -3 (IGFBP-3) to the oral glucose tolerance test (OGTT).

METHODS

the study included 24 women, aged 45-55 years, categorized into 4 groups, premenopausal pre-obese (BMI = 28.5 +/- 0.8 Kg/m2) and normal body weight (BMI = 22.2 +/-1.1 Kg/m2), and postmenopausal pre-obese and normal body weight. All women underwent: (1) a biophysical evaluation with determination of waist/hip ratio; (2) an assessment of fat and lean tissue mass and body fat distribution by total body DEXA; and to (3) an OGTT.

RESULTS

in response to OGTT plasma GH levels significantly decreased in all groups, but the relative decrease was more prominent in the lean subjects. A significant decrease of IGFBP-1 levels in response to OGTT was observed in all women, regardless of menopausal age and BMI, while IGFBP-3 levels did not significantly change in either group.

CONCLUSIONS

in conclusion, the impact of both BMI and menopausal condition on GH, IGFBP-1, and -3 response to OGTT is limited to a blunted GH response in overweight women compared with normally-weighing ones. These findings appear to rule out the hypothesis that a common glycometabolic derangement may affect both the modifications of body weight and of the somatotropic axis observed in perimenopausal women.

Growth factor action on ovarian function in polycystic ovary syndrome

Insulin-like growth factors, their receptors, binding proteins, and binding protein proteases are important in normal and abnormal ovarian follicle development. IGFs stimulate ovarian cellular mitosis and steroidogenesis and inhibit apoptosis. Patterns of expression of IGF family members are characteristic of whether follicles are estrogen- or androgen-dominant. The PCOS follicle is androgen-dominant but does not appear to be atretic and has characteristic IGF family expression. Available data strongly support an intraovarian, as opposed to endocrine, role for this growth factor family in ovarian follicle growth, steroidogenesis, and atresia.

Modification of plasma insulin-like growth factors and binding proteins during oral contraceptive use and the normal menstrual cycle

OBJECTIVE

Sex steroid regulation of the insulin-like growth factor axis is a subject of contention. We examined the effect of combined oral contraceptives and investigated the cyclic variations in the insulin-like growth factor axis.

STUDY DESIGN

Fasting blood samples were taken from 9 women receiving oral contraceptives, 10 women receiving no medication, and 10 male subjects.

RESULTS

In women receiving oral contraceptives, insulin-like growth factor binding protein 1 remained highly phosphorylated and levels were acutely increased by sex steroid treatment (305 +/- 110 microg/L on day 14 of the cycle [medication phase] vs 118 +/- 70 microg/L during the medication-free period, P <.03). In women receiving no medication, insulin-like growth factor binding protein 1 levels were significantly lower (69 +/- 50 microg/L on day 14 of the menstrual cycle, P <.001) and varied cyclically, with a rise in the late-secretory phase that coincided with the appearance of nonphosphorylated and less phosphorylated insulin-like growth factor binding protein 1 isoforms. Compared with those in untreated women and in men, insulin-like growth factor I levels were decreased in women receiving oral contraceptives (405 +/- 104 ng/mL in untreated women and 330 +/- 28 ng/mL in men vs 287 +/- 73 ng/mL in women receiving oral contraceptives, P <.004). Oral contraceptive use had no effect on insulin-like growth factor II levels, and neither insulin-like growth factor I nor insulin-like growth factor II showed cyclic variation.

CONCLUSION

The bioavailability of insulin-like growth factor I is reduced in users of oral contraceptives. This may contribute to the metabolic changes observed in such subjects.

Decline in insulin-like growth factor I levels after clomiphene citrate does not correct hyperandrogenemia in polycystic ovary syndrome

It is widely accepted that the action of clomiphene citrate (CC) is mediated through its antiestrogenic properties on the hypothalamic-pituitary axis. Although insulin-like growth factor I (IGF-I) enhances the thecal cell response to LH, and estrogen treatment is associated with a reduction in IGF-I levels, CC is known to decrease circulatory IGF-I levels in polycystic ovary syndrome (PCOS) patients. The impact of lowering IGF-I levels on androgen levels in PCOS is unknown. This study was designed to examine the impact of CC treatment on the interrelationships of IGF-I, androgens, and estrogens in normal subjects and patients with PCOS. IGF-I, gonadotropin, androgen, estrogen, and sex hormone-binding globulin levels were measured in 8 PCOS patients and 10 normal subjects before and after treatment with the antiestrogen CC. Studies were performed in the early follicular phase, days 4-6 of the menstrual cycle in normal subjects. In normal subjects, CC treatment led to a significant increase in estradiol (84 +/- 10 to 234 +/- 62 pmol/L, untreated and CC treated; P < 0.05) and estrone (125 +/- 14 to 257 +/- 29 pmol/L; P < 0.05) levels with a significant lowering of IGF-I levels (297 +/- 25 to 230 +/- 17 micrograms/L; P < 0.05). Similarly, in PCOS patients a significant increase in estradiol (110 +/- 11 to 245 +/- 58 pmol/L; P < 0.05) and estrone (301 +/- 32 to 401 +/- 90 pmol/L; P < 0.05) levels and a significant lowering of IGF-I levels (330 +/- 43 to 214 +/- 27 micrograms/L; P < 0.05) were observed after CC treatment. However, no significant correlation was observed between changes in IGF-I and changes in estradiol in either group. Compared to pretreatment levels, no significant changes in the following parameters were observed after 5 days of CC treatment in either study group: testosterone, testosterone/sex hormone-binding globulin ratio, and androstenedione. The relationship among CC treatment, gonadotropin, estrogen, and IGF-I levels is complex. Changes in blood IGF-I levels are not associated with changes in androgen levels, although paracrine and or autocrine effects cannot be excluded.

Combined oral contraceptives and gonadotropin releasing hormone agonistic analogs in polycystic ovary syndrome: clinical and experimental studies

Polycystic ovary syndrome is a common endocrine disorder, presenting with menstrual irregularities, hirsutism, obesity, infertility and abnormal ovarian morphology. In addition, polycystic ovary syndrome is associated with a self-perpetuating imbalance involving the endocrine system and metabolic pathways, in which carbohydrates, lipids and growth factors are involved. Because of its chronicity, it is considered to be a substantial risk factor for atherogenesis and hormone-dependent neoplasia. The etiology and pathophysiology of the syndrome remain elusive. However, during the last decade, several clues have emerged from human and animal studies that may have significant repercussions in the treatment of polycystic ovary syndrome. Therapeutic maneuvers should be directed towards the dominant abnormalities present in individual patients with polycystic ovary syndrome. Gonadotropin releasing hormone (GnRH) agonists can directly affect the gonadotropin generator and secondary downstream derangements, whereas combined oral contraceptives (COCs) can modify hypothalamic as well as peripheral abnormalities. In view of the fact that GnRH agonistic analogs (GnRH-a) will induce hypoestrogenemia and its sequelae, the add-back strategy of estrogenic supplementation is recommended for preventive reasons and, as it transpires from some studies, for enhancement of GnRH-a effectiveness.

Up-regulation of IGF binding protein-1 as an anticarcinogenic strategy: relevance to caloric restriction, exercise, and insulin sensitivity

The mitotic rate of stem cells is a major determinant of cancer risk. Insulin-like growth factors (IGFs) are virtually obligate stimulants of cell turnover in nearly every tissue. IGF activity is subject to rapid modulation by hepatic release of IGF binding protein-1 (IGFBP-1), a factor whose synthesis is suppressed by insulin and increased by glucagon. Up-regulation of IGFBP-1 production can be expected to decrease IGF activity and thereby diminish cancer risk. Measures that sensitize peripheral tissues to insulin, and thereby down-regulate insulin secretion, can be expected to increase IGFBP-1 synthesis, provided that they do not unduly sensitize hepatocytes as well. Prolonged aerobic exercise and caloric restriction also increase IGFBP-1 production. Since IGF-1 suppresses hepatic synthesis of sex hormone binding globulin (SHBG), down-regulation of IGF activity will increase SHBG levels and thus diminish the availability of free sex hormones--an effect that should further decrease cancer risk in sex hormone-responsive tissues. These considerations rationalize many findings in animal and epidemiologic studies, and suggest that non-diabetic insulin resistance may be a significant cancer risk factor. Increased IGF activity associated with insulin resistance may also promote benign hyperplasias-most notably atherosclerosis. Hyperinsulinemia stimulates intimal hyperplasia indirectly, via IGF.

The effect of monophasic combinations of ethinyl estradiol and norethindrone on gonadotropins, androgens and sex hormone binding globulin: a randomized trial

The effects of different monophasic combinations of ethinyl estradiol and norethindrone on FSH, LH, sex hormone binding globulin, total testosterone, androstenedione, and dehydroepiandrosterone sulfate levels in non-obese, non-hirsute women were compared. Retrospective analysis of frozen serum from a prospective randomized trial in which women received one of three oral contraceptive pills containing ethinyl estradiol 50 micrograms/norethindrone 1 mg, ethinyl estradiol 35 micrograms/norethindrone 1 mg or ethinyl estradiol 35 g/norethindrone 0.5 mg for nine cycles was conducted. Blood samples were obtained prior to treatment and during the third, sixth and ninth pill cycles. Ethinyl estradiol 50 micrograms/norethindrone 1 mg and ethinyl estradiol 35 micrograms/norethindrone 1 mg suppressed FSH, LH, and total testosterone and increased sex hormone binding globulin to a similar degree. Ethinyl estradiol 35 micrograms/norethindrone 0.5 mg resulted in less suppression of FSH, LH, and total testosterone, but greater elevation of sex hormone binding globulin. Dehydroepiandrosterone sulfate was suppressed to a similar degree with ethinyl estradiol 35 micrograms/norethindrone 1 mg and ethinyl estradiol 35 micrograms/norethindrone 0.5 mg, but ethinyl estradiol 50 micrograms/norethindrone 1 mg resulted in the least suppression of dehydroepiandrosterone sulfate. Ethinyl estradiol 35 micrograms/norethindrone 1 mg caused greater suppression of androstenedione than did the other two oral contraceptives. Oral contraceptive-induced changes in gonadotropins, androgens, and sex hormone binding globulin can be predicted by considering the relative amounts of estrogen and progestin in the pill. When combined with 1 mg of norethindrone, 50 micrograms of ethinyl estradiol did not result in greater suppression of FSH, LH, or total testosterone or in greater elevation of sex hormone binding globulin than did 35 micrograms of ethinyl estradiol.

Comparison of transdermal and oral estrogen therapy in girls with Turner's syndrome

Eight girls with Turner's syndrome were given low dose oral ethinyl estradiol or transdermal 17 beta-estradiol in order to compare the effect of the route of administration on selected markers of hepatic metabolism, and various hormonal concentrations. Oral estrogen was given at a dose of 100 ng/kg/day and transdermal estrogen via adhesive skin patch at 0.0125 mg/kg/day. The subjects received one form of estradiol for one month, and after a one month washout period, received the other form. Both oral and transdermal estradiol caused a significant decrease in FSH while only transdermal resulted in a significant decrease in LH. Oral estradiol, though not transdermal estradiol, increased serum high density lipoprotein, thyroxine binding protein and growth hormone binding protein. Urinary growth hormone excretion increased after both forms of therapy, while insulin-like growth factor-I and insulin-like growth factor binding protein-3 remained unchanged. Thus, in girls with Turner's syndrome, estrogen replacement by the transdermal route may have less deleterious effect on hepatic metabolism than oral estrogen.

Potential impact on breast cancer risk of circulating insulin-like growth factor I modifications induced by oral HRT in menopause

Unlike parenteral estrogens, oral estrogen administration in menopause causes, through its hepatocellular action, a significant decrease of circulating insulin-like growth factor I (IGF-I) levels; this effect is opposed by the addition of an androgenic progestogen. In vitro studies show that IGF-I is a potent mitogen for 'estrogen responsive' breast cancer cells. Moreover, some findings in breast cancer patients and in women treated with tamoxifen suggest that reduction of circulating IGF-I could be protective to the breast. However, by also considering (1) the potential action on breast cancer cells of IGF-II, (2) the possible consequences of the growth hormone (GH) increase caused by the IGF-I reduction and (3) the fact that in vitro results are not simply transferable to the in vivo condition, other 'scenarios' can be envisaged, besides the favorable one. In support of the latter, there are epidemiologic data which suggest that oral estrogen use could have some favorable peculiarities with regards to breast cancer risk. The associated decrease in circulating IGF-I level could well be one of these peculiarities.

Insulin-like growth factors: clinical experience in ovarian function

Insulin, insulin-like growth factor, and insulin-like growth factor binding proteins have been shown to play major roles in the modulation of both normal and disturbed ovarian physiology. Identification of many of the actions of these peptides was initially characterized using animal models. However, an increasing body of evidence has emerged to clarify their contributions in human reproductive function. It is clear that at various stages of folliculogenesis, local steroid production acts in concert with intraovarian peptides to promote dominant follicle development. This review will discuss the physiologic role(s) of the insulin-insulin-like growth factor-insulin-like growth factor binding protein family in reproductive function and disorders of androgen excess.

The response of the growth hormone and insulin-like growth factor I axis to medical castration in women with polycystic ovarian syndrome

OBJECTIVE

To assess the impact of ovarian hormone deprivation on serum concentrations of GH and insulin-like growth factor I (IGF-I) in women with polycystic ovarian syndrome (PCOS).

DESIGN

Growth hormone and IGF-I levels were measured before, during, and at the end of a 6-month period of treatment with leuprolide acetate (LA) depot. Normal cycling and ovariectomized women served as controls.

SETTING

The Clinical Research Center of Northwestern University Medical School.

PATIENTS

Six women with PCOS, seven normal cycling women, and six ovariectomized women.

INTERVENTIONS

The PCOS and normal cycling subjects were treated with six consecutive monthly injections of LA depot 3.75 mg IM.

MAIN OUTCOME MEASURES

Circulating concentrations of GH and IGF-I.

RESULTS

After 3 months of treatment, GH levels decreased modestly in the PCOS group; however, these changes were not significant. No further decline was observed at 6 months. Growth hormone levels were unaffected in the normal cycling group. Levels of IGF-I remained unchanged in both groups. Mean baseline levels of both GH and IGF-I in the ovariectomized group were lower than those of the normal cycling and PCOS groups at all time points, but not significantly so.

CONCLUSIONS

Medical castration fails to significantly alter serum GH and IGF-I levels in either normal cycling or women with PCOS. These data indicate that GH secretion is not modulated by hormones of ovarian origin in either group, at least over the period of time studied.

Plasma insulin-like growth factor I and its binding proteins 1 and 3 in postmenopausal patients with breast cancer receiving long term tamoxifen

BACKGROUND

Insulin-like growth factor I (IGF-I) is a potent mitogen for breast cancer cells. The majority of IGF-I in plasma is bound to IGF binding proteins (IGFBPs), which modulate the biologic effects of IGF-I.

METHODS

Plasma concentrations of IGF-I, IGFBP-I, and IGFBP-3 were compared between 40 postmenopausal breast cancer patients receiving long term tamoxifen therapy and 39 breast cancer patients receiving no hormonal treatment. In an additional group of seven patients, serum levels of IGF-I and IGFBP-1 were determined before and during treatment at 6 and 12 months.

RESULTS

The tamoxifen and the control groups did not differ with respect to age, parity, age at menopause, or body mass index. There were no significant differences in the mean concentrations (+/- standard error of the mean) of IGF-I (10.0 +/- 0.4 nmol/l and 11.2 +/- 0.5 nmol/l, respectively) and IGFBP-3 (3.2 +/- 0.1 mg/l and 3.1 +/- 0.1 mg/l, respectively), whereas the mean value of IGFBP-1 was significantly higher in the tamoxifen group (6.0 +/- 0.6 micrograms/l versus 2.8 +/- 0.3 micrograms/L, P = 0.0001). No significant differences were found in the insulin levels. During the treatment, concentrations of IGF-I decreased at 6 months and began increasing at 12 months. IGFBP-1 levels increased at 6 months and remained elevated at 12 months.

CONCLUSIONS

The tamoxifen-induced increase in IGFBP-1 plasma levels may be an important mechanism modulating IGF-I action at the tissue level.

Differential effects of oral conjugated estrogens and transdermal estradiol on insulin-like growth factor 1, growth hormone and sex hormone binding globulin serum levels

In postmenopausal women oral ethinylestradiol causes a reduction in circulating insulin-like growth factor 1 (IGF-1) and an increase in serum growth hormone levels. There are no data on the effect of conjugated estrogens, the preparation most often used in estrogen replacement treatment (ERT), on these parameters. We evaluated serum IGF-1 and growth hormone levels, together with the levels of sex hormone binding globulin (SHBG), an indicator of estrogen hepatocellular action, before and after 6 months of ERT in two comparable groups of postmenopausal women. Sixteen women were treated with oral conjugated estrogens, 0.625 mg/day, and 14 with transdermal estradiol, 0.05 mg/day. In the women treated with oral conjugated estrogens, an increase in SHBG (p < 0.001), a decrease in IGF-1 (p < 0.001) and an increase in growth hormone (p < 0.05) serum levels were observed. No such effects were seen with the use of transdermal estradiol, devoid of hepatocellular effects. Undoubtedly, oral conjugated estrogens, 0.625 mg/day, through a hepatocellular effect, cause marked modifications in the IGF-1/growth hormone axis, which may have clinical relevance. For instance, the decreased IGF-1 level, together with the increased level of SHBG, might provide some explanation of the favorable epidemiological data on breast cancer risk in women receiving oral conjugated estrogens.

Ovarian electrocauterization causes LH-regulated but not insulin-regulated endocrine changes

OBJECTIVE

We studied the effects of ovarian electrocauterization on the serum levels of luteinizing hormone (LH), testosterone, insulin, sex hormone-binding globulin (SHBG) and insulin-like growth factor binding globulin-1 (IGFBP-1) in women with polycystic ovarian disease (PCOD).

DESIGN

Prospective.

PATIENTS

Ten women with PCOD admitted to a University Infertility Clinic.

MEASUREMENTS

Fasting blood samples for determination of hormone levels were taken during the follicular phase before and one month after laparoscopic ovarian electrocauterization.

RESULTS

One month after electrocauterization the serum mean +/- SE LH levels had decreased from 14.4 +/- 1.9 to 10.9 +/- 1.1 U/l (P < 0.05), while the serum insulin levels showed no significant change (10.3 +/- 2.0 and 8.1 +/- 1.3 mU/l). The levels of IGFBP-1 (33.9 +/- 8.2 and 38.4 +/- 13.7 micrograms/l) and SHBG (48 +/- 10.4 and 43 +/- 5.7 nmol/l) showed no significant changes. Testosterone decreased from 3.9 +/- 2.6 to 2.9 +/- 0.3 nmol/l (P < 0.001) and androstenedione from 15.0 +/- 1.2 to 12.0 +/- 1.5 nmol/l (P = 0.05). After electrocautery seven out of ten PCOD patients ovulated either spontaneously (n = 3) or with clomiphene citrate (n = 4), and two of them conceived.

CONCLUSIONS

Ovarian electrocautery leads to resumption of ovulatory cycles in some but not all PCOD patients. This effect seems to be mediated by reduction of serum LH and androgen levels, while the insulin-driven pathway via SHBG and IGFBP-1 remains unaffected.

Serum levels of insulin-like growth factor binding protein-1 and ovulatory responses to clomiphene citrate in women with polycystic ovarian disease

OBJECTIVE

To study the serum levels of insulin, insulin-like growth factor I (IGF-I), and insulin-like growth factor binding protein-1 (IGFBP-1) in relation to clomiphene citrate (CC) responsiveness in women with polycystic ovarian disease (PCOD).

DESIGN

Prospective. PATIENTS, SETTING: Twenty-three women with PCOD admitted consecutively to the University Infertility Clinic, a tertiary referral center.

INTERVENTIONS

Blood samples were taken at fasting state and during oral glucose tolerance test (OGTT) for the determination of insulin, IGF-I, and IGFBP-1. A dose of 50 to 200 mg/d CC was given for ovulation induction.

RESULTS

With CC treatment, ovulation was achieved in 13 of 23 PCOD patients. The IGFBP-1 concentration was lower in CC nonresponders than in CC responders (20.5 +/- 4.0 ng/mL versus 41.0 +/- 8.5 ng/mL) (P < 0.05). This difference was accentuated in 13 lean PCOD patients. Lean CC nonresponders (n = 7) had almost threefold lower serum IGFBP-1 levels than lean CC responders (n = 6) (24.0 +/- 3.1 ng/mL versus 61.8 +/- 8.6 ng/mL) (P < 0.01). By contrast, among 10 obese PCOD patients, the IGFBP-1 levels were low irrespective of CC responsiveness (14.8 +/- 8.0 ng/mL versus 16.7 +/- 7.2 ng/mL). The differences remained during OGTT. The concentrations of IGF-I, insulin, sex hormone-binding globulin, LH, FSH, and androgens showed no significant differences between CC responders and nonresponders. There was an inverse correlation between serum insulin and IGFBP-1 levels in obese PCOD patients, whereas this was not seen in lean patients.

CONCLUSION

In lean PCOD patients, low serum IGFBP-1 concentration is related to CC unresponsiveness by a mechanism unrelated to insulin.

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.