胰岛素样生长因子I及其结合蛋白1对超排卵周期卵泡发育的影响

】     

Lack of insulin-like growth factor binding protein-3 variation after follicle-stimulating hormone stimulation in women with polycystic ovary syndrome undergoing in vitro fertilization.

OBJECTIVE: To investigate serum and follicular fluid (FF) insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) behavior in superstimulated cycles in patients with polycystic ovary syndrome (PCOS). DESIGN: Controlled clinical study. SETTING: Department of Obstetrics and Gynecology, University of Naples. PATIENT(S): Thirty-two patients with regular menses and tubal and/or male factor infertility and 21 patients with PCOS undergoing IVF. INTERVENTION(S): The IVF program used leuprolide acetate suppression followed by sequential hMG in the subsequent cycle. After follicular development, hCG administration was followed 34-36 hours later by oocyte retrieval. MAIN OUTCOME MEASURE(S): E2, GH, IGF-I, and IGFBP-3 assayed by RIA and immunoradiometric assay. RESULT(S): The controls and patients with PCOS showed similar increases in E2 and GH titers in response to FSH stimulation. Serum IGF-I did not change in either group and was equivalent in the FF. Patients with PCOS had a higher FF IGFBP-3 titer and did not show the decrease in serum IGFBP-3 levels of the control group after FSH stimulation. CONCLUSION(S): The apparent failure of IGFBP-3 reduction in patients with PCOS alters IGF-I bioavailability. Increased sequestration of IGF-I affects ovarian steroidogenesis and may explain the poor response to gonadotropin stimulation.     

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.     

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.     

Metformin therapy increases insulin-like growth factor binding protein-1 in hyperinsulinemic women with polycystic ovary syndrome

OBJECTIVES: Polycystic ovary syndrome (PCOS) is associated with hyperandrogenism, insulin resistance, compensatory hyperinsulinemia, and increased levels of free insulin-like growth factor-I (IGF-I), presumably due to a decline in IGF binding protein 1 (IGFBP-1). This study was designed to evaluate effects of metformin therapy on serum levels of IGFBP-1 and IGF-I. STUDY DESIGN: Twenty-seven obese, hyperandrogenic PCOS women with elevated fasting insulin were treated for 12 weeks with metformin (500 mg p.o., t.i.d.). Serum levels of insulin, testosterone, sex hormone binding globulin (SHBG), IGF-I, and IGFBP-1 were measured before and after treatment. Body mass index (BMI) and waist-to-hip ratio (WHR) were assessed at baseline and at the end of therapy. RESULTS: Metformin therapy significantly increased IGFBP-1 concentration by 38% (P = 0.05) but had no demonstrable effect on the total IGF-I levels. Fasting insulin levels declined by 38% (P = 0.0001) while the glucose/insulin ratio increased by 72% (P = 0.0001) and quantitative insulin sensitivity check index (QUICKI) increased by 8% (P = 0.0001). Metformin treatment also significantly decreased testosterone (by 37%, P = 0.0001) and increased SHBG concentration (by 16%, P = 0.04). Multiple linear regression analysis revealed that baseline IGFBP-1 levels correlated inversely and independently with two baseline parameters: WHR (P = 0.003) and free testosterone index (P = 0.04). CONCLUSIONS: The present study shows that metformin therapy not only restores normal levels of insulin and testosterone, but also decreases the pool of free-bioactive IGF-I by increasing the levels of circulating IGFBP-1. We provide further arguments in favor of metformin therapy in hyperinsulinemic women with PCOS.     

Ovulation induction increases serum levels of insulin-like growth factor binding protein 1.

The effect of ovulation induction on serum insulin-like growth factor binding protein 1 (IGFBP-1) level in relation to sex hormone binding globulin (SHBG) levels was evaluated. Serum samples were collected 8 to 12 days after ovulation from 26 women undergoing ovulation induction with clomiphene citrate (CC), and from 58 women treated with CC in combination with human menopausal gonadotropin (hMG) and human chorionic gonadotropin (hCG). In addition, serum samples were obtained from 63 spontaneously ovulating women and from 12 women during an anovulatory cycle. Luteal phase serum IGFBP-1 levels were 4.22 +/- 2.95 micrograms/L (P less than .05) in the CC group and 7.31 +/- 6.13 micrograms/L (P less than .001) in the CC/hMG/hCG group as compared to unstimulated ovulatory cycles (2.64 +/- 2.52 micrograms/L). No significant difference in IGFBP-1 levels was seen between spontaneously ovulatory and anovulatory cycles. The serum IGFBP-1 levels correlated positively to SHBG levels (r = .52, P less than .001). The data show that ovulation induction increases serum IGFBP-1 levels in parallel to SHBG levels, indicating that ovarian stimulation, which results in increased steroid hormone production, also induces changes in other factors known to modulate steroid hormone actions.     

Increased insulin-like growth factor-I levels in women with polycystic ovary syndrome, and beneficial effects of metformin therapy.

We aimed to investigate whether metformin would reverse the endocrinopathy of polycystic ovary syndrome (PCOS), allowing resumption of cyclic ovulation and regular menses, and whether metformin causes any change in the serum concentration of insulin-like growth factor-I (IGF-I) in patients with PCOS. Fifty-eight women with PCOS participated in the study and received metformin at a dose of 850 mg three times a day (total 2550 mg) for 16 weeks. Serum concentrations of luteinizing hormone, follicle stimulating hormone, estradiol, free testosterone, total testosterone, 17-hydroxyprogesterone, dehydroepiandrosterone sulfate, fasting insulin, IGF-I, sex hormone binding globulin and insulin-like growth factor binding protein-1 (IGFBP-1) were evaluated before and after metformin treatment. Patients were divided into two groups as responders and non-responders according to the achievement of regular menstrual periods. The mean IGF-I levels decreased significantly on metformin therapy. After 16 weeks of metformin treatment, 55.17% of PCOS patients achieved regular menses. Only the change in serum levels of progesterone and IGF-I on metformin were statistically significant between responders and non-responders; metformin-induced decremental change in IGF-I levels were greater in responders. In conclusion, we observed that elevated IGF-I levels may have a crucial role in many consequences of PCOS in addition to hyperinsulinemia. By decreasing insulin and IGF-I levels, metformin therapy offers additional beneficial effects in resumption of regular menses. Thus, in PCOS patients with elevated levels of IGF-I, metformin may be considered as an appropriate agent to be used for the regulation of menstrual cycles.     

Follicular Fluid Insulin-like Growth Factor-I and Insulin-like Growth Factor–Binding Protein-1 and -3 Vary as a Function of Ovarian Reserve and Ovarian Stimulation

Purpose: Follicular fluid concentrations of insulin-like growth factor (IGF)-I, IGF-II, IGF-binding protein (BP)-1, and IGFBP-3 in 57 women undergoing in vitro fertilization and embryo transfer were examined to determine whether levels reflected differences in patients' exposure to gonadotropin stimulation and a diminished ovarian reserve. Methods: Preovulatory follicular fluid was obtained from both gonadotropin-stimulated and unstimulated cycles. Subjects were grouped according to normal or decreased ovarian reserve and whether or not they received gonadotropin stimulation. Results: The mean follicular fluid concentrations of IGF-I and IGFBP-1 were significantly lower in the decreased ovarian reserve group compared with the normal ovarian reserve group, with no change in estradiol or IGF-II levels. This resulted in a decreased molar IGF-I: BP ratio and an increased molar IGF-II:IGFBP-1 ratio. In unstimulated cycles, mean follicular fluid concentrations of IGFs did not differ significantly compared with those in stimulated cycles, whereas concentrations of IGFBP-1 and IGFBP-3 were significantly lower, leading to higher molar ratios of the IGFs to the binding proteins. Conclusions: Follicular fluid IGF and binding proteins vary as a function of ovarian reserve and gonadotropin stimulation. This may reflect either differences in oocyte quality or a suboptimal follicular fluid environment.     

Puberty and polycystic ovarian syndrome: the insulin/insulin-like growth factor I hypothesis.

OBJECTIVES: To provide an up-to-date review of studies that have examined the physiological effects of insulin and insulin-like growth factor I (IGF-I) on ovarian growth, maturation, and steroid synthesis, their physiological role in puberty, and their pathophysiological role in polycystic ovarian syndrome (PCOS). To deduce from these data a hypothesis, explaining the pathogenetic connections between puberty and PCOS. DATA IDENTIFICATION: The most relevant studies related to this topic have been identified through a computerized bibliographic search (MEDLINE) and through manual scanning of what has been published during recent years in the most important journals in the field of reproductive endocrinology. RESULTS: Insulin and IGF-I stimulate ovarian growth and potentiate the actions of gonadotropins on ovarian steroid synthesis. Insulin also augments the bioactive concentrations of IGF-I and androgens through regulation of the synthesis of their respective binding proteins insulin-like growth factor-1 binding protein (IGFBP-1) and sex hormone-binding globulin (SHBG) in the liver. Insulin and IGF-I might also be able to increase the adrenal sensitivity to adrenocorticotropic hormone (ACTH). Insulin resistance with compensating hyperinsulinism is a common feature of PCOS. It is also a normal phenomenon during puberty. Polycystic ovarian syndrome often develops during puberty. Ultrasonographic investigations suggest that it is much more common during adolescence than generally assumed. Actually, there is a striking resemblance between the endocrine characteristics of puberty and some forms of PCOS. Both conditions are characterized by insulin resistance, hyperpulsatile gonadotropin secretion, hyperactive ovarian and adrenal androgen synthesis, and decreased levels of IGFBP-1 and SHBG. CONCLUSION: We propose the progressively increasing insulin levels and IGF-I activity during puberty as inducing factors in the development of PCOS in susceptible subjects.     

Serum insulin-like growth factor (IGF)-I, IGF binding protein (IGFBP)-3, leptin concentrations and insulin resistance in benign and malignant epithelial ovarian tumors in postmenopausal women.

AIMS: The aims of the present study were to determine the serum concentrations of insulin-like growth factor-I (IGF-I), insulin-like growth factor binding protein-3 (IGFBP-3) and leptin and insulin resistance in benign and malignant epithelial ovarian tumors, and to discuss the use of these markers in benign-malignant tumor differentiation. METHODS: Forty-seven postmenopausal women with ovarian tumor and 31 age-matched, postmenopausal, healthy controls were included in this study. Insulin resistance index by homeostasis model assessment (HOMA score) and fasting blood glucose (FBG), serum IGF-I, IGFBP-3, leptin and CA-125 concentrations were determined in all patients preoperatively. The results were evaluated according to postoperative histopathology results. RESULTS: According to postoperative histopathology results, the patients were divided into malignant (n = 23), benign (n = 24) and control (n = 31) groups. There were no differences among the groups in relation to age, body mass index, FBG and HOMA score (p > 0.05). Serum concentrations of CA-125 were elevated in the malignant group compared with the benign ovarian tumor and control groups (p < 0.05). In contrast, serum IGF-I concentrations were significantly decreased in patients with malignant and benign ovarian tumors compared with controls (p < 0.05). Serum IGFBP-3 concentrations were also found to be lower in women with malignant ovarian tumors than in women with benign tumors (p < 0.05). Serum leptin did not differ among patients with malignant-benign tumors and controls (p > 0.05). CONCLUSION: Serum leptin and HOMA score have not been found to be valid indicators in ovarian tumors. However, the present data suggest that low concentrations of IGF-I and IGFBP-3 could be a reliable marker to differentiate benign from malignant ovarian tumors. Further experimental studies are warranted to understand the impact of the IGF-I system in ovarian carcinogenesis.     

Abnormalities in the serum insulin-like growth factor-1 axis in women with hyperandrogenism

Objective: To study the insulin-like growth factor-1 (IGF-1) axis in hirsute women.

Design: Controlled clinical study.

Setting: Tertiary care institutional hospital.

Patient(s): Forty hirsute women and 17 women with normal menstrual cycles.

Intervention(s): Basal and ACTH-stimulated samples were obtained, and sampling was repeated 1 (gonadal stimulation) and 21 (gonadal suppression) days after a single 3.75-mg IM dose of triptorelin. Controls did not receive triptorelin for ethical reasons.

Main Outcome Measure(s): Serum GH, IGF-1, IGF-binding protein-3 (IGFBP-3), insulin, glucose, total testosterone, sex hormone-binding globulin, E₂, and gonadotropin levels. Basal and ACTH-stimulated steroid precursors were measured.

Result(s): Patients with idiopathic hirsutism were identified by normal serum androgen levels (n = 17). Those with functional ovarian hyperandrogenism (n = 15) were identified by an increase in the serum testosterone level that normalized during gonadal suppression, whereas those with functional adrenal hyperandrogenism (n = 8) were identified by an initial increase in the testosterone level that persisted during gonadal suppression. The adrenal hyperandrogenism group had increased IGF-1 levels compared with the control, idiopathic hirsutism, and ovarian hyperandrogenism groups. Patients with ovarian hyperandrogenism had normal IGF-1 concentrations, but their IGFBP-3 concentrations were lower than those of controls. No differences were observed in GH levels between any of the groups. These results persisted when the influence of age was corrected for.

Conclusion(s): The IGF-1 axis appears to be involved in the pathogenesis of hyperandrogenism, especially in patients with adrenal hyperandrogenism, who have a clear increase in IGF-1 levels. Moreover, patients with ovarian hirsutism have decreased IGFBP-3 concentrations, which might enhance IGF-1 bioavailability.     

Maternal insulin-like growth factor-I levels (IGF-I) reflect placental mass and neonatal fat mass

OBJECTIVE: This study was undertaken to test the null hypothesis that serial changes in maternal insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding-protein-1 (IGFBP-1) levels during pregnancy do not reflect differences in either corrected birth weight or placental mass at term.Study design Serial blood samples were obtained before pregnancy and at 8, 16, 24, 32, and 38 weeks from 56 healthy women enrolled in various exercise training regimens. Maternal, placental, and fetal morphometric parameters were monitored throughout. Enzyme-linking immunosorbent assays were used to determine IGF-I and IGFBP-1 levels. RESULTS: IGF-I and IGFBP-1 levels varied widely among the subjects at all time points, but there was a consistent fall in IGF-I levels in early pregnancy, followed by a rapid increase between 16 and 36 weeks' gestation, whereas IGFBP-1 levels rose in the first 16 weeks and were unchanged thereafter. The strongest linear correlations with morphometric outcome were between the increase in maternal IGF-I levels from 16 to 32 weeks and corrected birth weight (r(2)=0.27), neonatal fat mass (r(2)=0.65), and placental mass at term (r(2)=0.50). These were improved when maternal glucose level was included in a stepwise regression analysis (r(2)=0.50-0.70). CONCLUSION: There is a robust relationship among the rate of increase in individual maternal IGF-I levels after 16 weeks, placental mass, and neonatal fat mass. This does not imply causality but does indicate that midpregnancy changes in IGF-I levels may be a valuable marker for anomalous fetal growth.     

Effects of conjugated equine estrogen vs. raloxifene on serum insulin-like growth factor-i and insulin-like growth factor binding protein-3: a 2-year, double-blind, placebo-controlled study

OBJECTIVE: To assess and compare the effect of conjugated estrogen and of the selective estrogen receptor modulator raloxifene on serum levels of insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) and on the IGF-I/IGFBP-3 ratio. DESIGN: A 2-year randomized, double-blind, placebo-controlled study. SETTING: Endocrinology outpatient department. PATIENT(S): Fifty-six postmenopausal, hysterectomized women. INTERVENTION(S): Women received raloxifene hydrochloride in doses of 60 mg/day (n = 15) or 150 mg/day (n = 13), conjugated equine estrogen (CEE) in doses of 0.625 mg/day (n = 15), or a placebo (n = 13) over the course of 2 years. MAIN OUTCOME MEASURE(S): At baseline and after 6, 12, and 24 months of treatment, serum levels of IGF-I, IGFBP-3, and insulin were measured, and an IGF-I/IFGBP-3 ratio was calculated. RESULT(S): Both raloxifene and CEE decreased serum IGF-I concentration. In contrast to CEE, which had no effect, both raloxifene doses of 60 and 150 mg/day significantly increased serum IGFBP-3 during the 2 years. Compared with placebo, the decrease in IGF-I/IGFBP-3 ratio was -32.5% (95% CI: -20.1; -44.8%) for CEE; -16.4% (95% CI: -3.6; -29.2%) for raloxifene at 150 mg/day; and -15.4% (95% CI: -1.0; -29.8%) for raloxifene at 60 mg/day. No effect of CEE or raloxifene was found on insulin concentration at any time point. CONCLUSION(S): Long-term use of both CEE and raloxifene decreases serum IGF-I and the IGF-I/IGFBP-3 ratio, but, unlike CEE, raloxifene produced a significant yet small increase in IGFBP-3.     

Effect of estradiol on the pituitary response to intravenous stimulation with luteinizing hormone-releasing hormone in menopausal women

Five menopausal patients were submitted to stimulation with 100-micrograms doses of luteinizing hormone-releasing hormone (LH-RH) administered 120 minutes apart under three different types of conditions: (1) in a hypoestrogenic state (test 1); (2) in a hyperestrogenic state after acute intravenous bolus injection of 400 micrograms 17 beta-estradiol (E2) (test 2); (3) in a hyperestrogenic state after daily oral administration of 50 micrograms ethinyl E2 for 3 to 4 weeks (test 3). The results of the three tests showed that (1) the time needed to reach maximum LH values after LH-RH injection was longest in test 3; (2) the hormonal production rate (HPR) in test 1 was greatest after the first stimulus with LH-RH. In test 2, the two stimulations with LH-RH induced an equivalent HPR, whereas in test 3, the HPR was greatest after the second stimulation; (3) the correlation between basal LH values before LH-RH injection and the maximal values of the responses obtained after each injection changed throughout the experiment. In all three tests, the slope of the line (significant positive correlation) was always greater after the second stimulation. When the three tests were compared, the slope in test 3 was greater than in test 2, and the slope in test 2 greater than in test 1. These results clearly suggest the important role of estrogens in the regulation of LH release in women by acting not only at the hypothalamus but also at the pituitary level, and demonstrate a correlation between basal LH levels and the maximum response to LH-RH stimulation. This correlation is more marked during estrogen treatment and depends on the time of exposure to estrogen.     

多囊卵巢综合征胰岛素抵抗与卵巢局部IGF-I系统的相关性研究

目的探讨卵巢局部胰岛素样生长因子-I(IGF-I)系统在PCOS胰岛素抵抗发病机制中的作用。方法选择30例PCOS胰岛素抵抗患者为研究组,30例输卵管性不孕患者为对照组。测定并比较两组的血清、小卵泡液中IGF-I、胰岛素样生长因子结合球蛋白-1(IGFBP-1)及各项性激素、糖代谢及卵巢超声指标,分析其与各项指标之间的相关性。结果研究组小卵泡液IGF-I高于对照组和其血清水平(P0.01),血清和小卵泡液的IGFBP-1低于对照组(P0.05,P0.01),小卵泡液IGFBP-1水平低于血清(P0.05)。研究组小卵泡液IGF-I与总睾酮(T0)、雌二醇(E2)及卵巢体积(OV)、卵巢总面积(TA)、卵泡数(FN)、空腹胰岛素(FI)和口服葡萄糖后2h胰岛素(2h胰岛素)呈正相关(r分别为0.94、0.51、0.52、0.49、0.65、0.76和0.58,P值均0.05);血清IGF-I与胰岛素敏感指数(ISI)、体重指数(BMI)和腰臀比(WHR)呈正相关(r分别为0.47、0.61和0.58,P0.05),与定量胰岛素敏感指数(QUICKI)呈负相关(r=-0.34,P0.05);研究组小卵泡液及血清IGFBP-1与FINS、2h胰岛素呈负相关(r=-0.48,P0.001;r=-0.39,P0.05;r=0.54,P0.05;r=-0.52,P0.05)。结论 PCOS患者的外周胰岛素抵抗可能通过影响卵巢局部IGF-I系统,刺激卵巢组织产生大量雄激素,导致排卵障碍。     

Plasma insulin, IGF-I and breast cancer

Several recent epidemiological studies have shown an increase in breast cancer risk among women who have elevated plasma levels of testosterone, reduced levels of sex hormone-binding globulin (SHBG), and hence elevated levels of bioavailable androgens and estrogens not bound to SHBG. This endocrine profile is generally associated with obesity and chronic hyperinsulinemia, of which it is most likely a result. Lack of physical activity, obesity, and a diet rich in rapidly digestible carbohydrates and poor in fibre favour the development of insulin resistance and hyperinsulinemia. The elevated insulin levels, in turn are related to decreases in plasma and tissue levels of IGFBP-1 and IGFBP-2 (insulin-like growth factor-binding proteins), and this may increase the availability of insulin-like growth factor-I (IGF-I) to its receptors. Like insulin, IGF-I also inhibits the hepatic synthesis of SHBG, whereas both hormones stimulate the ovarian synthesis of sex steroids. Moreover, insulin and IGF-I can both enhance the development of breast tumours, through their cognate receptors within the mammary tissue. Taken together, these observations lead to the hypothesis that breast cancer risk may be increased in women with elevated plasma insulin levels, and/or with elevated levels of bioactive IGF-I. Hyperinsulinemia and an increased IGF-I bioactivity could thus be an important physiological link between a western lifestyle, overnutrition, a hyperandrogenic sex steroid profile, and increased breast cancer risk. Prospective cohort studies will be needed to test this hypothesis, and to study in greater detail the possible relationships of breast cancer risk with plasma levels of IGF-I and IGFBPs. Confirmation of a relationship of breast cancer risk with plasma insulin levels, on the one hand, or with total plasma IGF-I, on the other hand, could open up new perspectives for breast cancer prevention, either by changes in dietary intake patterns and physical activity, or by the use of certain chemopreventive drugs.     

Leptin,VEGF, IGF-1, and IGFBP-3 concentrations in serum and follicular fluid of women undergoing in vitro fertilization

We studied the influence of recombinant follicle-stimulating hormone (rFSH) stimulation on the concentration of leptin, vascular endothelial growth factor (VEGF), insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) in serum and follicular fluid (FF) in women undergoing assisted reproduction. To test the hypothesis that these hormones could predict successful implantation and that the levels correlate with pregnancy rate. Sequential serum samples were drawn at the beginning of stimulation and on the day of embryo transfer (ET) from 84 women undergoing IVF. The follicular fluid (FF) obtained during oocyte retrieval was collected and the concentration of leptin, VEGF, IGF-1 and IGFBP-3 were measured in all samples. The hormones were measured by commercially available IRMA, RIA or EIA. Patients' characteristics and results of the assisted reproductive cycles were registered. Serum concentrations of VEGF, IGF-1 and IGFBP-3 significantly decreased during rFSH treatment. In contrast, serum leptin significantly increased after rFSH treatment. A strong correlation was found between the FF - levels of IGF-1, IGFBP-3, leptin and respective serum levels. With regard to IVF outcome, higher serum concentrations of IGF-1, IGFBP-3 and VEGF on the day of oocyte retrieval were observed in conception cycles vs. non-conception cycles. No such difference, however, was apparent at the beginning of the stimulation cycle. There was no association between FF levels of any of these hormones and IVF outcome. Our results demonstrate that VEGF, IGF-1, IGFBP-3 and leptin levels are affected by rFSH during controlled ovarian hyperstimulation and that there is a direct association between serum and FF levels, albeit without clinical implications     

Raised serum levels of matrix metalloproteinase-9 in women with polycystic ovary syndrome and its association with insulin-like growth factor binding protein-1

Background.?It has been suggested in recent studies that matrix metalloproteinases (MMPs) may be implicated in the pathogenesis of polycystic ovary syndrome (PCOS) through regulating ovarian tissue remodeling. In addition to degrading the extracellular matrix, MMPs exhibit the ability to cleave insulin-like growth factor binding protein-1 (IGFBP-1), the major regulator of insulin-like growth factor-I (IGF-I) in serum. The present study aimed to investigate the possible role of MMPs in the pathophysiology of PCOS.

Methods.?Serum levels of MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), IGF-I and IGFBP-1 were measured in 42 patients with PCOS and 30 healthy women with regular menstruation, matched for age and body mass index. Correlation between IGFBP-1 and other parameters in the PCOS group was analyzed by Pearson's linear correlations.

Results.?Serum MMP-9 concentrations and MMP-9/TIMP-1 ratios were significantly higher in PCOS women than in controls. Serum levels of IGFBP-1 were markedly lower in the PCOS group. There was a negative correlation between serum IGFBP-1 and MMP-9 in women with PCOS.

Conclusion.?Our results raise the possibility that MMPs may be implicated in the pathophysiology of PCOS either by regulating ovarian tissue remodeling or indirectly by facilitating IGF-I bioavailability through proteolysis of IGFBP-1.     

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.     

Serum insulin, insulin-like growth factor-I, and insulin-like growth factor binding protein-1 in women who develop preeclampsia

OBJECTIVE: To determine whether second-trimester serum concentrations of insulin, insulin-like growth factor-I (IGF-I), and insulin-like growth factor binding protein-1 (IGFBP-1) were altered in women before they developed clinical signs of preeclampsia. METHODS: A nested case-control study used serum obtained during second-trimester pregnancies from 12 women who developed preeclampsia matched with 24 controls who remained normotensive. Nine preeclamptic subjects and 18 controls were necessary to have 80% power to discern a 20% difference between groups with regard to the analytes under consideration. RESULTS: There were no significant differences between cases and controls with respect to many demographic factors. Women who developed preeclampsia had insulin concentrations that were not significantly different from controls, but serum concentrations of IGF-I were significantly higher and IGFBP-1 were significantly lower than those of the controls. The IGF-I/IGFBP-1 ratio helped to identify those at risk for developing preeclampsia. CONCLUSIONS: Serum concentrations of IGF-I and IGFBP-1 were abnormal long before women manifested clinical evidence of preeclampsia in this study. These alterations might be related to abnormalities in trophoblastic invasion and prove useful as potential markers for the identification of women who are at high risk of developing preeclampsia.