Phosphorylation of insulin-like growth factor-binding protein-1 from different sources

During purification, insulin-like growth factor binding protein-1 from amniotic fluid was separated into five different peaks by anion exchange chromatography. These peaks represent differently phosphorylated forms of IGFBP-1. The major peak (peak 1) is non-phosphorylated. Peaks 3, 4, and 5 are more phosphorylated and, in native polyacrylamide gel electrophoresis (PAGE), they migrate faster than peaks 1 and 2. The more phosphorylated forms have higher IGF-I-binding affinity. Both dephosphorylated and phosphorylated peaks enhanced IGF-I stimulated DNA-synthesis in fetal skin fibroblast cell culture. They, however, inhibited the binding of IGF-I to the same cells. The phosphorylation of IGFBP-1 was changed during pregnancy. In decidua and in amniotic fluid the degree of phosphorylation increased from early to late pregnancy, as indicated by faster mobility of IGFBP-1 in native PAGE and increased relative amount of the more phosphorylated peaks in anion exchange chromatography. Human ovarian follicular fluid, culture media from human granulosa cells and endometrial adenocarcinoma cells (HEC-1-B) consisted mostly of the non-phosphorylated form of IGFBP-1.

Tri-iodothyronine and cycloheximide enhance insulin-like growth factor-binding protein-1 gene expression in human hepatoma cells

The growth-regulating actions of IGFs are modulated by their binding proteins (IGFBPs). The serum concentration of IGFBP-1 is down-regulated by insulin, and in-vitro studies have demonstrated that IGFBP-1 secretion from various tissues and cells can be stimulated by theophylline, forskolin, oestrogen and progesterone. We have studied the effects and mechanisms of thyroid hormone action on IGFBP-1 gene expression and secretion by human hepatoma cells in vitro. Tri-iodothyronine dose-dependently enhanced IGFBP-1 secretion in serum-free HepG2 cell cultures after 24-48 h of exposure, as measured by a specific immunofluorometric assay. This was accompanied by an increase (+ 50%) in the amount of IGFBP-1 mRNA, which could be prevented by cycloheximide, a protein synthesis inhibitor. Cycloheximide transiently enhanced (+ 200%) the accumulation of IGFBP-1 mRNA at 3-12 h of incubation, when no effect of tri-iodothyronine was observed. It is concluded that thyroid hormone stimulates IGFBP-1 secretion slowly by enhancing IGFBP-1 gene expression by a protein mediator. The acute stimulation of IGFBP-1 gene transcription by cycloheximide associates this gene with a number of growth-related genes encoding growth- and tumour-associated peptides.

Effect of tamoxifen alone and in combination with RU 486 on the endometrium in the mid-luteal phase

The effects of RU 486 combined with tamoxifen and tamoxifen alone on hormonal parameters and endometrial development at the time of implantation were studied. Measurements of cytosolic oestrogen and progesterone receptors in endometrium and placental protein 14 (PP14) in plasma were also included. Three dosage schedules were used: single oral dose of 40 mg tamoxifen alone and in combination with 200 mg RU 486, and 40 mg tamoxifen for three consecutive days starting on the first day after the luteinizing hormone (LH) surge. The combined treatment prolonged the luteal phase (P < 0.05) and increased the plasma levels of progesterone. A single dose of tamoxifen did not affect the bleeding pattern and plasma hormone levels, but raised plasma oestradiol and LH with the 3-day treatment. The endometrium was retarded after the combined and the 3-day treatment with tamoxifen. Concentrations of cytosolic progesterone receptors were higher after the combined therapy, but were unaffected after tamoxifen only. PP14 levels were higher (P < 0.05) after repeated tamoxifen doses than in controls, but were lower with combined treatment. Progesterone and oestrogen are evidently necessary for endometrial maturation during the secretory phase of the menstrual cycle. PP14 levels in plasma cannot be used for clinical assessments of endometrial function because high levels coincide with disturbed endometrial development.

Localization of progesterone-associated endometrial protein mRNA by in-situ hybridization in human pregnancy decidua, endometriosis and borderline endometrioid adenoma

Progesterone-associated endometrial protein (PAEP) has been isolated from human decidualized endometrium. In-situ hybridization histochemistry was employed to determine the cellular localization of PAEP mRNA in decidua during pregnancy. PAEP mRNA was found to be expressed in the glandular epithelium of decidua spongiosa throughout pregnancy. Substantial variations in the amount of PAEP mRNA during the course of pregnancy were observed, and it was most abundant at the end of the first trimester. We also found that the PAEP gene was expressed in endometriosis and in a borderline endometrioid adenoma. As in decidual tissues, PAEP mRNA in endometriosis was abundant in the glandular compartment.

Prevalence and characteristics of symptomatic gastroesophageal reflux disease in the elderly

OBJECTIVE

To study prevalence and characteristics of symptomatic gastroesophageal reflux disease in the elderly.

DESIGN

Survey by questionnaire of stratified random sample.

SETTING

City of Turku, Finland.

SUBJECTS

Population-based random sample consisting of non-institutionalized subjects aged 65 years or over. A questionnaire was sent to 559 subjects. The response rate was 92%. Twenty-nine incompletely filled forms were rejected. Thus, the questionnaires from 487 subjects, representing 87% of the original number, constitute the basis for the study.

MEASUREMENTS

The questionnaire inquired about the following symptoms: heartburn, regurgitation, chest pain, dysphagia, dyspepsia, respiratory symptoms, vomiting, and belching.

RESULTS

The age-adjusted prevalence of daily symptoms suggestive of gastroesophageal reflux disease was 8% in men and 15% in women (P < 0.05). Fifty-four percent of men and 66% of women reported that they had symptoms at least once a month (P < 0.05). The prevalence of symptoms was roughly the same across age groups. The occurrence of chest pain, dyspepsia, vomiting, belching, dysphagia, chronic cough, hoarseness, and wheezing were associated with symptoms suggestive of gastroesophageal reflux disease.

CONCLUSIONS

Symptoms suggestive of gastroesophageal reflux disease are common in elderly subjects. Women suffer from these symptoms more frequently than men. Typical reflux symptoms are often associated with atypical complaints, such as abdominal symptoms, chest pain, or respiratory symptoms.

Growth hormone and insulin-like growth factor regulate insulin-like growth factor-binding protein-1 in Laron type dwarfism, growth hormone deficiency and constitutional short stature

Insulin-like growth factors (IGFs) mediate the effects of growth hormone (GH), and the insulin-like growth factor-binding proteins (IGFBPs) modulate the actions of IGFs in tissues. We studied the circulating levels of IGFBP-1 in 6 children and 9 adults with Laron type dwarfism (LTD), in 11 children and 21 adults with growth hormone deficiency (GHD), and in 8 children with constitutional short stature. Compared with the situation in healthy children, the basal serum IGFBP-1 concentration was 5.4-fold higher in LTD children, 4.1-fold higher in GHD children, and 3.8-fold higher in children with short stature (p < 0.02 vs controls in all groups). In adult patients with multiple pituitary hormone deficiency (MPHD), the IGFBP-1 concentration was 2-fold elevated, but it was normal in adult LTD patients. Intravenous (N = 10) or subcutaneous (N = 9) administration of IGF-I (75 micrograms.kg-1 and 150 micrograms.kg-1, respectively) in LTD children resulted in a rapid 50-60% fall in serum insulin (p < 0.02), a decline in blood glucose and a concomitant 40-60% rise of IGFBP-1 levels (p < 0.05). Treatment for seven days with IGF-I (150 micrograms.kg-1 x d-1) resulted in a decrease by 34% and 44% of serum IGFBP-1 level in two out of three children with LTD. After prolonged GH therapy, the IGFBP-1 level fell in GHD children by 29% (p < 0.05), in GHD adults by 52% (p < 0.02) and in children with constitutional short stature by 17% (p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of endocrine therapy with medroxyprogesterone acetate, 4-hydroxyandrostenedione or tamoxifen on plasma concentrations of insulin-like growth factor (IGF)-I, IGF-II and IGFBP-1 in women with advanced breast cancer

Tamoxifen treatment of women with advanced breast cancer has previously been reported to reduce plasma insulin-like growth factor-type I (IGF-I) concentrations. In this study we have examined the effect of treatment with Tamoxifen, medroxyprogesterone acetate (MPA) or 4-hydroxyandrostenedione (4-OHA) on plasma IGF-I and IGF-II concentrations. As IGF-binding proteins (IGFBPs) can modulate the biological effects of IGF-I, plasma IGFBP-I levels were also measured. Treatment with Tamoxifen for 2 weeks resulted in a small, but significant, decrease in IGF-I levels, but increase in the plasma concentration of IGFBP-I. In contrast, treatment with MPA increased levels of IGF-I, but significantly reduced plasma IGFBP-I concentrations. Treatment with 4-OHA had no significant overall effect on plasma IGF-I or IGFBP-I levels, although changes were detected for some subjects. Plasma IGF-II concentrations were not altered by treatment with Tamoxifen, MPA or 4-OHA. It is concluded that although treatment with Tamoxifen or MPA produced significant changes in plasma IGF-I concentrations, any physiological effects of such changes are likely to be modulated by the corresponding alterations in plasma IGFBP-I concentrations.

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.

Expression of insulin-like growth factor binding protein-1 mRNA in human fetal kidney

Expression of insulin-like growth factor binding protein-1 (IGFBP-1) messenger RNA (mRNA) was studied in tissues of human fetuses from 15 to 23 weeks of gestation. Northern blot analysis revealed IGFBP-1 mRNA in the fetal liver and kidney but not in other fetal tissues, including the brain, heart, lung, skeletal muscle and spleen. Studies by in situ hybridization histochemistry showed that, in all fetal kidneys tested, the IGFBP-1 mRNA was localized preferentially to the epithelial cells of the collecting ducts, as well as to the cells of developing glomeruli and in the subcapsular nephrogenic mesenchyme. Less intense labeling for IGFBP-1 mRNA was seen in the connective tissue stroma of the medullary pyramids. A weak signal was detected in the mature glomeruli, and in the cells of the medullary mesenchyme and capsular connective tissue. IGFBP-1 protein was detected by immunoperoxidase staining mostly around small blood vessels but not in the respective endothelium. The protein was also present in many epithelial cells of the collecting ducts and in stromal connective tissue. These results show that the predominant sites of IGFBP-1 transcription in the developing kidney are those with most active differentiation.

Insulin-like growth factor-I and follicle-stimulating hormone suppress insulin-like growth factor binding protein-1 secretion by human granulosa-luteal cells

Local regulation of insulin-like growth factor binding protein-1 (IGFBP-1) production in the human ovarian follicle was investigated using cultured human granulosa-luteal cells. Both insulin-like growth factor-I (IGF-I) and follicle-stimulating hormone (FSH) exerted a dual effect on granulosa cells: while estradiol (E2) production was increased by both stimulants, the addition of either of the two hormones led to a reduction in IGFBP-1 secretion by more than 50%. Inhibition of IGFBP-1 production in response to IGF-I was dose-dependent,with the highest effect observed at 5 nM IGF-I. A significant correlation was found between the increase in E2 and inhibition of IGFBP-1 secretion in response to IGF-I. These observations may suggest a novel mechanism, at the follicular level, by which FSH and IGF-I amplify the IGF-I effect in the ovarian follicular cells.

Epidermal growth factor stimulates production of insulin-like growth factor-binding protein-1 in human granulosa-luteal cells

Insulin-like growth factor-I (IGF-I) enhances and epidermal growth factor (EGF) inhibits gonadotrophin-induced aromatization in granulosa cells. Our previous studies have shown that human ovarian granulosa cells synthesize insulin-like growth factor-binding protein-1 (IGFBP-1) which inhibits IGF-stimulated DNA synthesis. The present study addresses the effect of EGF and gonadotrophins in the regulation of IGFBP-1 release by human granulosa cells cultured in serum-free medium. At concentrations of 1-100 micrograms/l EGF was found to stimulate IGFBP-1 secretion. This was not due to cell proliferation, as the viable cell count remained unaffected. Growth hormone and gonadotrophins had no effect on IGFBP-1 secretion when added alone to culture medium. These results suggest that EGF regulates IGFBP-1 secretion in human granulosa-luteal cells.

Endometrial proteins: a reappraisal

Uterine factors influence reproduction at the macro-anatomy level, and the effects of hormonal steroids on endometrial morphology are well recognized in the histopathological diagnosis of dysfunctional bleeding and infertility. During the past decade, attention has been paid to endometrial protein synthesis and secretion with respect to endocrine stimuli and implantation, and to the paracrine/autocrine effects of endometrial peptide growth factors, their binding proteins and other factors. The emphasis of this presentation is on protein secretion of the secretory endometrium, in which progesterone plays a pivotal role. Insulin-like growth factors have receptors on the endometrium, and IGF-binding proteins, stimulated by progesterone, modulate the effects of IGFs locally. Also other protein products of the secretory endometrium have been reviewed in this communication, with special emphasis on studies of a progesterone-associated endometrial protein which has many names in the literature, such as PEP, PP14, alpha 2-PEG and AUP. Extensive studies are ongoing in many laboratories to elucidate the regulation, function, interplay at tissue and cellular levels, and clinical significance of these proteins.

Insulin-like growth factor-I (IGF-I) may not be essential for ovarian follicular development: evidence from IGF-I deficiency

Insulin-like growth factor-I (IGF-I) stimulates growth and differentiation in follicular granulosa cells (GC). To examine whether this effect is prerequisite to human folliculogenesis, a patient with Laron-type dwarfism (IGF-I deficiency secondary to GH receptor abnormality) was examined while undergoing in vitro fertilization treatment. Despite low levels of IGF-I in serum and follicular fluid (less than 3 and less than 2 nmol/L) and very high levels of IGF-I-binding protein, the patient developed normal ovarian follicles. After the administration of GnRH analog (GnRHa) and human menopausal gonadotropin in a dose similar to that used in normovulatory women, estradiol (E2) levels reached above 5000 pmol/L on the day of hCG administration, and mature fertilizable oocytes were retrieved during ovum pickup. The patient's GC E2 production, tested in a primary culture, did not respond to IGF-I after 4 days of incubation, while control cultures showed a significant increase. Only after a priming period of 7 days did IGF-I have a significant effect on E2 production, as observed in the patient's GC culture. This delayed response suggests that the patient's GC were not exposed in vivo to IGF-I. Our data support the view that IGF-I is not required for normal follicular development, but is, rather, a nonessential modulator of FSH action.

Placental protein 14 in human in-vitro fertilization early pregnancies

Placental protein 14 (PP14) and human chorionic gonadotrophin (HCG) were analysed in patients participating in an in-vitro fertilization-embryo transfer programme which did not include any kind of luteal support. Women with normal pregnancies, spontaneous abortions, ectopic pregnancies, biochemical pregnancies and non-pregnant women were compared. A combination of HCG and PP14 analyses distinguished between normal and abnormal implantation as early as 15 days after oocyte retrieval. The product of HCG (IU/l) and PP14 (micrograms/l) concentrations differed significantly between normal pregnancy, spontaneous abortion and ectopic pregnancy (P = 0.0248). It is concluded that both endometrial (PP14) and trophoblastic (HCG) markers, when used in combination, exhibit changes in abnormal implantation which may be clinically useful.

Suppression by human placental protein 14 of natural killer cell activity

Human decidua of early pregnancy contains considerable numbers of CD3-CD56+ natural killer (NK) cells. In this study, two major protein products of the decidua, placental protein 14 (PP14) and placental protein 12 (PP12), were tested for the ability to regulate human NK cell activity. In vitro overnight exposure to PP14 of blood lymphocytes or purified large granular lymphocytes (LGL) resulted in suppression of cytotoxicity against K562 target cells in a 4-h 51Cr release assay. The NK inhibition was dependent on concentrations of PP14, being detectable at 5 micrograms/ml and reaching maximum at 50 micrograms/ml. Manifestation of PP14-induced NK suppression required 18-h contact with NK cells. The suppression of NK activity by PP14 was not abolished by indomethacin. In a target binding assay the number of PP14-treated LGL binding to K562 was comparable to that of untreated ones. By contrast with PP14, PP12 produced no effects on NK cells. These results indicate that PP14 suppresses the function of NK cells, which might be involved in prevention of maternal immune rejection of fetus at the fetomaternal interface.

Expression of endometrial protein PP14 in pelvic and ovarian endometriotic implants

Localization and immunohistochemical staining patterns of endometrial protein PP14 were studied in 55 patients providing 86 histologically confirmed pelvic and ovarian endometriotic implants. The cellular localization of PP14 in endometriotic implants is comparable with that in the endometrium: epithelial cells express PP14, whereas stromal cells are negative. Positive immunostaining is restricted to apical secretory-like granules of the epithelial cells. In endometriotic implants with positive staining, PP14 is expressed by some, but not all, glandular epithelial cells. Furthermore, positive staining for PP14 is observed most frequently in foci with in-situ secretory differentiation, whereas implants with proliferative or atrophic implants only rarely express PP14. Finally, PP14 can be localized in endometriotic foci at different depths of infiltration, although positive labelling is seen more often in superficial implants. These data demonstrate that PP14 can be expressed by endometriotic glandular epithelial cells with secretory cellular differentiation and that the histological appearance of ectopic implants sometimes only poorly reflects their function.

Insulin-like growth factor binding protein-1 and ovarian stimulation

Serum concentrations of insulin-like growth factor binding protein-1 (IGFBP-1) were measured in 42 patients with tubal infertility undergoing two different regimens of ovarian stimulation for in-vitro fertilization. The first group comprised 24 women given a luteinizing hormone-releasing hormone agonist analogue (buserelin, LHRHa) on cycle days 1-4 followed by follicle-stimulating hormone and human menopausal gonadotrophin (LHRHa group). The second group of 18 women received clomiphene citrate and gonadotrophins (CC group). On the day of human chorionic gonadotrophin administration, the sum of follicular diameters (P less than 0.05) and the number of follicles punctured in the LHRHa group (P less than 0.01) were significantly higher than in the CC group. In spite of the greater number of follicles, the oestrogen levels were similar in both groups, but women in the LHRHa group had significantly higher serum IGFBP-1 concentrations during the last 5 days of stimulation. These results suggest that the stimulated preovulatory follicles may contribute to the elevation of serum IGFBP-1.

HinfI polymorphism in the human progesterone associated endometrial protein (PAEP) gene

Images

Insulin-like growth factor binding protein-1 inhibits the DNA amplification induced by insulin-like growth factor I in human granulosa-luteal cells

In order to study the effects of insulin-like growth factor (IGF-I) and insulin-like growth factor binding protein (IGFBP-1) on human granulosa cell proliferation after in vitro fertilization, cells were obtained after oocyte retrieval and cultured in the presence or absence of graded amounts of recombinant IGF-I, purified IGFBP-1 and [3H]thymidine. Physiological concentrations of IGF-I (2-200 ng/ml) were found to stimulate [3H]thymidine incorporation into the cells in a concentration-dependent manner. Half-maximal stimulation of [3H]thymidine incorporation was obtained with 10 ng/ml exogenous IGF-I, which was chosen for suppression experiments with graded amounts of purified IGFBP-1. Suppression of IGF-stimulated thymidine incorporation was observed when 200 ng/ml or more of IGFBP-1 was added to the culture medium. The same concentration of IGFBP-1 also markedly inhibited binding of [125I]iodotyrosyl IGF-I to the cells. It is concluded that: (i) after a refractory period, granulosa cells from hyperstimulated follicles retained their mitogenic activity; (ii) IGF-I is capable of stimulating DNA amplification in granulosa cells; and (iii) IGFBP-1 inhibits the IGF-I stimulated proliferation in these cells. In view of our previous studies showing that IGFBP-1 is synthesized by the granulosa cells as they luteinize, the present results suggest that IGFBP-1 is one of the endogenous factors locally regulating the growth and differentiation of granulosa cells.

Short and long term effects of growth hormone on circulating levels of insulin-like growth factor-I (IGF-I), IGF-binding protein-1, and insulin: a placebo-controlled study

The short and long term effects of GH on serum concentrations of insulin-like growth factor-I (IGF-I), IGF-binding protein-1 (IGFBP-1), and insulin were investigated in women participating in an in vitro fertilization program. In this placebo-controlled study, sterile saline (eight women) or 24 IU GH (eight women) were given im on alternate days, starting on cycle day 4, in combination with GnRH and human menopausal gonadotropin. IGFBP-1 levels decreased significantly during the first 4 h after GH administration, whereas no significant changes were seen in the placebo group. The concentrations of serum IGF-I and insulin did not change during 4 h after GH injection. During the 11-day follow-up period, serum levels of both IGF-I and insulin were significantly higher in GH-treated than in placebo-treated women. These results suggest that the serum concentration of IGFBP-1 is not completely GH independent. They also support the earlier findings that long term treatment with GH increases serum IGF-I and insulin levels.

Polycystic ovary syndrome: evolution of a concept

Despite improved diagnostic facilities and advanced in vitro studies, the primary causes of the polycystic ovary syndrome (PCOS) have not been resolved. In addition to certain enzyme deficiencies causing a PCOS-like state, current evidence indicates altered functions of 5 alpha-reductase and cytochrome P450c17 alpha in PCOS patients as a group. However, it is not obvious if these are primary or secondary to the abnormal hormonal milieu. The relation of insulin-like growth factors (IGFs) to PCOS is of particular interest in view of the occurrence of IGF-II mRNA in the granulosa cells and the ability of IGF-I to regulate the granulosa cell and thecal-interstitial cell functions. In obese PCOS patients, the levels of sex hormone binding globulin and IGF-binding protein-1 are subnormal in serum, and fasting increases them. Fasting also suppresses high insulin and IGF-I concentrations in the same women. Growth hormone, regulated by insulin and probably by IGF-I, appears to be decreased in PCOS patients. Follicular growth, characteristically arrested in PCOS, is regulated by growth hormone to some extent, and growth hormone treatment has been found to improve the ovarian response to gonadotropins in some but not all anovulatory patients. In addition to the administration of growth hormone itself, therapeutic measures modulating the growth hormone-ovarian axis are being studied. High serum luteinizing hormone levels are typical of PCOS. These are often associated with infertility and early pregnancy loss. Lowering of the luteinizing hormone levels by a gonadotropin-releasing hormone analogue in combination with gonadotropins improves the outcome of pregnancies as compared with those achieved by clomiphene citrate. The use of the former regimen in PCOS patients may result in ovarian hyperstimulation. Ovarian electrocautery has proved to be effective in restoring cyclicity of ovarian function with a concomitant fall in luteinizing hormone and androgen levels. Interestingly, an increase in serum insulin secretion has been noted. It remains to be elucidated if this therapy, followed by decreased luteinizing hormone, is effective in reducing the elevated risk of miscarriages in women with PCOS.