help button home button Endocrine Society JCEM JCEM Call for Nominations for EIC
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Journal of Clinical Endocrinology & Metabolism, doi:10.1210/jc.2006-1678
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
92/6/2066    most recent
Author Manuscript (PDF)
Right arrow Submit a related Letter to the Editor
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Gambineri, A.
Right arrow Articles by Pasquali, R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Gambineri, A.
Right arrow Articles by Pasquali, R.
Related Collections
Right arrow Female Endocrinology
The Journal of Clinical Endocrinology & Metabolism Vol. 92, No. 6 2066-2073
Copyright © 2007 by The Endocrine Society

Insulin-Like Factor 3: A New Circulating Hormone Related to Luteinizing Hormone-Dependent Ovarian Hyperandrogenism in the Polycystic Ovary Syndrome

Alessandra Gambineri, Laura Patton, Rosaria De Iasio, Federica Palladoro, Uberto Pagotto and Renato Pasquali

Division of Endocrinology, Department of Internal Medicine and Centre for Applied Biomedical Research, S. Orsola-Malpighi Hospital, University of Bologna, 40138 Bologna, Italy

Address all correspondence and requests for reprints to: Renato Pasquali, M.D., Division of Endocrinology, Department of Internal Medicine, S. Orsola-Malpighi Hospital, Via Massarenti 9, 40138 Bologna, Italy. E-mail: renato.pasquali{at}unibo.it.


   Abstract
Top
 Abstract
Introduction
 Subjects and Methods
 Results
 Discussion
 References
 
Context: Insulin-like factor 3 (INSL3), a member of the relaxin-insulin family, is produced in the Leydig cells and at reduced levels in ovarian theca interna cells of antra follicles as well as in the corpora lutea and ovarian stroma. Among the factors potentially involved in the stimulation of gonadal expression of INSL3, recent data obtained in rats show an important role of LH. Ovaries from most women affected by polycystic ovary syndrome (PCOS) are characterized by hyperplasia of the theca interna and of cortical stroma and by an increased number of small antral follicles, and the majority of women with PCOS, particularly normal-weight subjects, have LH levels that are above the normal range.

Objective: The objective of this study was to investigate INSL3 circulating levels in both normal-weight and overweight-obese PCOS women and the association of INSL3 with gonadotropin and androgenic pattern and with ovarian morphology.

Design: This was a controlled study.

Setting: The study took place at an academic hospital.

Participants: The participants included 44 PCOS patients (22 normal-weight and 22 overweight-obese) and 44 controls comparable for age and body weight.

Main Outcome Measures: The main outcome measures included INSL3 serum concentrations, measured by RIA, in PCOS patients and controls and their correlation with clinical and biochemical phenotype and with ovarian morphology.

Results: INSL3 serum concentrations were significantly higher in PCOS patients with respect to controls (P = 0.003), particularly in normal-weight (P = 0.001) but not in overweight-obese (P = 0.312) PCOS patients. INSL3 serum concentrations were positively correlated with total and free testosterone and with LH levels in all women (total testosterone, P < 0.001; free testosterone, P = 0.001; LH, P = 0.002) as well as in PCOS patients (total testosterone, P = 0.024; free testosterone, P = 0.045; LH, P = 0.049). Moreover, in the PCOS group, INSL3 levels were related to a greater 17OH-progesterone response to buserelin (P = 0.015), an index of ovarian hyperandrogenism. Finally, in PCOS women, INSL3 levels were positively correlated with ovarian follicle number (P = 0.028).

Conclusions: INSL3 could be considered a new circulating hormone related to LH-dependent ovarian hyperandrogenism, particularly in normal-weight PCOS women.


   Introduction
Top
 Abstract
 Introduction
Subjects and Methods
 Results
 Discussion
 References
 
INSULIN-LIKE FACTOR 3 (INSL3) is a new circulating peptide hormone of the relaxin-insulin family. In male mammals, including humans, it is a major secretory product of the testicular Leydig cells, in which it appears to be expressed constitutively but in a differentiation-dependent manner (1).

In the adult testis, INSL3 is a good marker for fully differentiated adult-type Leydig cells, but it is only weakly expressed in prepubertal immature Leydig cells or in Leydig cells that have become transformed. It is also an important product of the fetal Leydig cell population, in which it has been demonstrated to be responsible for the second phase of testicular descent acting on the gubernaculums (2). Male INSL3 knockout mice exhibit, in fact, bilateral cryptorchidism (3, 4). INSL3 is also synthesized in the ovary, particularly in the theca interna cells of antra follicles (at a higher level in small antral follicles than in larger, presumably preovulatory, follicles), as well as in the corpora lutea and ovarian stroma (1, 5, 6). As in the testis, INSL3 expression is constitutive, but differentiation dependent also in the ovary, and seems to be importantly related to gonadal function (1). Female INSL3 knockout mice show impaired fertility associated with extension of the estrous cycle length (7) and accelerated follicular atresia and luteolysis, with the premature loss of corpora lutea in ovaries, probably because of increased apoptosis (8). These results, in association with the coincidence of the appearance of growing follicles with the beginning of INSL3 expression in mouse ovaries and the finding that, in the cyclic ovary, higher INSL3 is expressed in the follicular phase than in the luteal phase, suggest a correlation of INSL3 with follicular maturation (2). This is further supported by the observation that INSL3 expression by the theca interna of bovine follicles dynamically changes with follicle development, with INSL3 levels highest at the early antral stages but declining as follicles enter a maturation pathway to become preovulatory follicle or enter atresia (the default pathway) (9).

No sufficient information about the factors potentially involved in the regulation of the tissutal expression of INSL3 is available as yet. However, recent data obtained in rats suggest an important role of LH in stimulating INSL3 transcripts at ovarian thecal cells and testicular Leydig cells (10). Human studies seem to support this hypothesis, because a significant positive correlation between INSL3 and LH concentration has been found in normal adult men (11). Moreover, patients with hypogonadotropic hypogonadism show very low INSL3 concentrations, which are increased by human chorionic gonadotropin treatment (11).

Ovaries from most women affected by polycystic ovary syndrome (PCOS), a hyperandrogenic disorder of ovarian and/or adrenal origin, are characterized by an hyperplasia of the theca interna and cortical stroma and by an increased number of small antral follicles when compared with normal ovaries (12). These follicles are not atretic; instead, their growth is prematurely arrested, resulting in the failure of dominant follicle development and ovulation (13), and, interestingly, their number is positively related to the ovarian androgenic function, as assessed by the serum free testosterone response to a dexamethasone-androgen suppression test and by the ovarian steroid responses to nafarelin (12). In addition, many women with PCOS have LH levels above the normal range (14). However, this condition seems to be particularly evident in normal-weight rather than obese PCOS women (15, 16), depending on reduced LH pulse amplitude and reduced LH response to GnRH stimulation related to the obese state (15).

With this background, we measured INSL3 circulating levels in both normal-weight and overweight-obese women with PCOS compared with appropriate control groups, matched for age and body weight. In addition, within the PCOS group, we investigated the association of INSL3 with the gonadotropin and androgenic pattern and with ovarian morphology.


   Subjects and Methods
Top
 Abstract
 Introduction
 Subjects and Methods
Results
 Discussion
 References
 
Subjects

We investigated 44 women with PCOS, aged 18–45 yr, and 44 controls matched for age and body weight. PCOS women had the following two criteria: chronic oligo-anovulation [luteal serum progesterone <2 ng/ml (17)]; and hirsutism [Ferriman-Gallwey score of ≥8 (18)] or elevated serum testosterone levels [>2 SD above our reference mean values (>0.75 ng/ml], obtained in normal-weight ovulatory women, (19), according to the National Institutes of Health 1990 criteria (20). Hyperprolactinemia, Cushing’s syndrome, congenital adrenal hyperplasia, and androgen-secreting tumors were excluded by specific laboratory analysis (21). Controls had no signs of hyperandrogenism (hirsutism, acne, and androgenetic alopecia) and normal ovulatory menstrual cycles. Ovulation was documented by the presence of progesterone levels above 8 ng/ml during the luteal phase of the menstrual cycle, tested through the recruitment period (17). The degree of obesity was established depending on the body mass index (BMI) values, and women were classified as normal weight if BMI was greater than 18 kg/m2 and no more than 25 kg/m2 and overweight-obese if BMI was greater than 25 kg/m2 and less than or equal to 30 kg/m2 or more than 30 kg/m2, respectively (22). Twenty-two PCOS patients were normal weight, 4 were overweight, and 18 were obese. Within controls, 22 were normal weight and 22 were obese. All subjects did not take any medication for at least 3 months before the recruitment in the study, and none had thyroid dysfunction, diabetes, or cardiovascular, renal, or liver diseases. The protocol was approved by the local ethics committee, and written informed consent was obtained from each patient and controls.

Assessment program

Standard anthropometric data (height, weight, and waist and hip circumferences) were obtained from all PCOS and control women, as described previously (21). Basal blood samples for hormonal [LH, FSH, total testosterone, androstenedione, 17OH-progesterone, dehydroepiandrosterone sulfate (DHEA-S), estradiol, and SHBG], metabolic (glucose and insulin), and INSL3 determinations were also collected at 0800–0830 h, after an overnight fast. One the same day, all participants also underwent a fasting 75 g oral glucose tolerance test (OGTT). The day after, starting from 0800 h, dexamethasone at 0.5 mg orally, one tablet every 6 h for 5 consecutive days, was given to PCOS women only, to suppress adrenal steroidogenesis. On day 4, at 0800–0830 h, two blood samples, at 15 min intervals, were obtained to measure gonadotropin (LH and FSH) concentrations, and a single blood sample was obtained to measure total testosterone, androstenedione, 17OH-progesterone, and DHEA-S (these samples were the baseline for buserelin test). Thereafter, buserelin (Suprefact, Hoechst, Germany), a GnRH agonist, at 100 µg, was administered sc, and blood was taken for the measurements of LH and FSH after 30 and 60 min. Twenty-four hours later at 0800–0830 h, two blood samples, at 15 min intervals, were taken for LH and FSH measurements, and a single sample was taken for total testosterone, androstenedione, 17OH-progesterone, and estradiol determinations. Buserelin test was used to analyze ovarian function. Samples were immediately chilled on ice, centrifuged, and stored at –80 C until assayed.

Thirty-five PCOS women also underwent an ultrasound evaluation of the ovaries. Whenever possible, the exam was performed transvaginally with a 7.5 MHz transvaginal probe. In four subjects, ultrasonography was performed transabdominally using a 5 MHz abdominal probe. Ovarian volume was calculated using the simplified formula for a prolate ellipsoid (23), and the ovary with the larger volume was reported. The follicle number was obtained counting the total number of 2–9 mm follicles in the longitudinal cross-section of the ovary. The number of follicles of the ovary with the larger number of follicles was reported. All subjects had polycystic ovaries, in particular an increased ovarian volume (>10 ml) and/or 12 or more follicles measuring 2–9 mm in diameter in at least one ovary (24). All of the evaluations were performed in the early follicular phase of the menstrual cycle in controls and in PCOS women with mild-to-moderate oligomenorrhea or at random in PCOS women with severe oligomenorrhea or amenorrhea, after excluding pregnancy by appropriate testing.

Biochemical assays

The assays used for biochemical measurements have been reported previously (21, 25, 26). The free androgen index (FAI) was calculated as the ratio between total testosterone and SHBG, according to Vermeulen et al. (27).

Analysis of INSL3

Serum samples for immunoreactive INSL3 concentration analysis were assayed in duplicate by using a commercial RIA (Phoenix Pharmaceutical, Belmont, CA). The assay is based on a polyclonal rabbit antiserum raised against full-length human INSL3 and on 125I-labeled INSL3 as the tracer. The assay performance was checked before analysis by verifying specificity, sensitivity, precision, and accuracy. To detect the specificity, a cross-reactivity test was conducted via a binding assay with decreasing concentrations of human insulin, INSL4, INSL5, INSL6, and INSL7. The sensitivity was determined as the lower detection limit (28). The precision was checked by using replicates of a serum pool control to measure intraassay and interassay variability. Finally, to detect the accuracy of the method, linearity of dilution was determined by serially diluting serum pool control, and recovery was evaluated by measuring pooled serum samples spiked with increasing standard human INSL3 concentrations before analysis in the RIA. Cross-reactivity with human insulin, INSL4, INSL5, INSL6, and INSL7, used to evaluate the specificity of the INSL3 assay, was 0%. The sensitivity determined as the lower detection limit was 1.8 pg/ml. The intraassay and interassay coefficients of variation were 3.1 and 6.8%, respectively. Suitability of the assay to measure INSL3 accurately was demonstrated by results of linearity and recovery (slope of 1; mean of recovery of 104%), which demonstrated the absence of bias.

Statistical analysis

Data are shown as means ± SD, unless otherwise indicated. The response of glucose and insulin to the OGTT was analyzed by calculating the area under the curve (AUC) by the trapezoidal method. Hormone response to the buserelin test was measured from the concentrations enriched on day 4 of the dexamethasone administration (baseline) and 24 h after buserelin injection. The response of LH and FSH to buserelin was analyzed by calculating the AUC. The arithmetic means of the two gonadotropin values obtained during the same test at baseline and 24 h later were included as single time points in the calculation of the AUC. A one-way ANOVA was applied to compare values between PCOS women and controls. The effect of PCOS within normal-weight and overweight-obese subjects was evaluated by means of nesting design of two-way ANOVA. The overall effect of PCOS and of overweight-obesity in the entire population (each adjusted for the other) and the interactions between them were also evaluated by means of two-way ANOVA. Simple correlation analyses were used to relate INSL3 with clinical, biochemical, and morphological parameters. Statistical analyses were performed by running the SPSS/PC+ version 8 (SPSS, Chicago, IL) (29) and the BMDP (BMDP Statistical Software, Berkeley, CA) (30) software packages. Two-tailed P values <0.05 were considered statistically significant.


   Results
Top
 Abstract
 Introduction
 Subjects and Methods
 Results
Discussion
 References
 
Table 1Go shows clinical and biochemical characteristics in PCOS and control groups and those of the subgroups of PCOS and controls with normal weight or overweight-obesity.


View this table:
[in this window]
[in a new window]

  		TABLE 1. Clinical, hormonal, and metabolic characteristics in PCOS women and controls

 
PCOS women and controls were of similar age and BMI. They also had similar waist and waist to hip ratio values, glucose and insulin fasting levels, and glucose response to the glucose load. However, PCOS women had higher response of insulin to OGTT and, as expected, higher levels of androgens (total testosterone, FAI, and androstenedione) and LH, lower levels of SHBG and estradiol, higher hirsutism scores, and a lower frequency of menstruation when compared with controls. Differences between PCOS women and controls on androgen levels (total testosterone and androstenedione) were more evident in the normal-weight subgroup than in those with overweight-obesity, whereas difference between PCOS women and controls on the response of insulin to OGTT was more evident in the overweight-obese subgroup. Notably, basal LH levels were higher in normal-weight PCOS subjects than in their counterpart, whereas a borderline significant difference was found between overweight-obese PCOS women and controls.

Figure 1Go shows INSL3 concentrations in PCOS and control groups and those of the subgroups of PCOS women and controls with normal weight or overweight-obesity.


Figure 1
View larger version (6K):
[in this window]
[in a new window]

  		FIG. 1. INSL3 levels in controls and PCOS women, expressed as mean ± SD. P values refer to the comparison between controls and PCOS women evaluated by ANOVA. The effects of PCOS (42.2; 95% CI of 15.3–69.1; P = 0.002), overweight-obesity (10.9; 95% CI of –16.0 to 37.8; P = 0.424), and their interaction (–45.6; 95% CI of –99.4 to 8.3; P = 0.056) on INSL3 levels were estimated in the entire population by two-way ANOVA.

 
PCOS women had higher levels of INSL3 when compared with controls (P = 0.003). However, when PCOS women and controls were classified according to BMI, this difference persisted only between the two normal-weight subgroups (P = 0.001) but disappeared between those with overweight-obesity (P = 0.312). When we estimated the effect of PCOS, overweight-obesity, and their interaction on INSL3 concentrations in the entire population by two-way ANOVA, we found that PCOS status was associated with higher INSL3 levels [effect of 42.2; 95% confidence interval (CI) of 15.3–69.1; P = 0.002], whereas the presence of overweight-obesity had no significant effect (effect of 10.9; 95% CI of –16.0 to 37.8; P = 0.424). We also found a borderline significance in the estimation of the effect produced by the interaction between PCOS and overweight-obesity (effect of –45.6; 95% CI of –99.4 to 8.3; P = 0.056), which further supports the idea that the influence of PCOS on INSL3 concentrations is restricted to normal-weight individuals.

Within the entire population, levels of INSL3 were not related to age (r = 0.12; P = 0.430), BMI (r = 0.16; P=0.125), waist circumference (r = 0.14; P = 0.209), or waist to hip ratio (r = 0.02, P = 0.889). In contrast, they were significantly and positively correlated with total testosterone (Fig. 2AGo) and FAI (Fig. 2BGo) and with LH basal concentrations (Fig. 2CGo). They were also positively correlated with the hirsutism score (r = 0.29; P = 0.013) and negatively correlated with the frequency of menstruation (r = 0.46; P < 0.001). However, no significant correlations were found between INSL3 and FSH, estradiol, androstenedione, 17OH-progesterone, DHEA-S, SHBG, glucose and insulin basal concentrations, and glucose and insulin response to OGTT.


Figure 2
View larger version (18K):
[in this window]
[in a new window]

  		FIG. 2. Relationship between INSL3 and total testosterone (A), FAI (B), and LH (C) measured in basal condition within the entire population ({circ}, controls; •, PCOS).

 
The positive significant correlation between INSL3 and total testosterone, FAI, and LH basal concentrations (Fig. 2Go, A–C) and the lack of relationship of INSL3 with androstenedione, 17OH-progesterone, DHEA-S, and FSH values still persisted in the PCOS group. In addition, in PCOS women, levels of INSL3 were positively correlated with the peak plasma 17OH-progesterone concentration in response to buserelin (Fig. 3Go) but not with that of androstenedione, testosterone, and estradiol or with the response (as AUC) of LH and FSH.


Figure 3
View larger version (9K):
[in this window]
[in a new window]

  		FIG. 3. Relationship between INSL3 and the peak plasma 17OH-progesterone (17OH-Prog) concentration in response to buserelin within the PCOS cohort.

 
Finally, a significant positive correlation was found of INSL3 values with the ovarian follicle number, calculated on the ovary with the larger number of follicles (Fig. 4Go) but not with the homolateral ovarian volume (r = 0.08; P = 0.622).


Figure 4
View larger version (9K):
[in this window]
[in a new window]

  		FIG. 4. Relationship between INSL3 and the ovarian follicle number, calculated on the ovary with the larger number of follicles, within the PCOS cohort.

 
LH basal concentrations were positively correlated with total testosterone (r = 0.36; P=0.001) and FAI (r = 0.22; P = 0.047) within the entire population. Within the PCOS cohort, LH basal levels were positively correlated with total testosterone (r = 0.33; P = 0.030), but not with FAI (r = 0.08; P = 0.635), and with the peak plasma 17OH-progesterone concentration in response to buserelin (r = 0.67; P < 0.001). No significant correlation between LH basal levels and the ovarian follicle number was found (r = 0.31; P = 0.065).


   Discussion
Top
 Abstract
 Introduction
 Subjects and Methods
 Results
 Discussion
References
 
This study shows that circulating levels of INSL3, a peptide almost exclusively of gonadal origin, are related to PCOS status and are associated with higher LH levels, with increased basal and ovarian hyperandrogenemia and hirsutism score, with worsened menstrual pattern, and with higher mean ovarian follicle number in women with PCOS. Interestingly, increased levels of INSL3 were particularly evident in normal-weight, rather than in overweight-obese, PCOS subjects. The coexistence of high INSL3 and high LH in normal-weight PCOS women and the significant positive correlation between INSL3 levels and LH or testosterone concentrations strongly support a cause-and-effect relationship. As reported previously in studies performed in men (11), it is likely that, in normal-weight PCOS women, increased LH may be responsible, at least in part, for increased androgen secretion from the ovarian tissues through the regulatory action of INSL3. This may reinforce the concept that a pathophysiological heterogeneity exists in the factors responsible for androgen excess in PCOS women, according to their phenotype.

Increased LH levels are a common finding in PCOS, particularly in normal-weight individuals. Conversely, LH pulsatile secretion is markedly disturbed by the presence of obesity. In fact, a negative correlation between LH blood levels and body weight has been found in PCOS women (31). Therefore, PCOS women with excess body weight are characterized by significantly lower LH concentrations than the normal-weight counterparts, frequently resembling the normal range (31). This is attributable to the fact that, with increasing body weight, LH pulse amplitude tends to linearly decrease, as does the LH response to GnRH (31). In contrast, several studies have shown that, in obese PCOS women, particularly in the presence of the abdominal phenotype, the degree of hyperandrogenemia tends to be worse with respect to that observed in normal-weight PCOS (31). This implies that other factors relatively independent of neuroendocrine regulation may be responsible for increased ovarian androgen production in obese PCOS women. It is likely that hyperinsulinemia, which accompanies the insulin-resistant state, a common condition found in overweight or obese PCOS women, plays a pivotal role in this context (32, 33).

Given the potential implication of INSL3 in the regulation of ovarian function, our data, showing a significant relationship between LH and INSL3, particularly in normal-weight PCOS women, are therefore intriguing. The mechanisms responsible for increased INSL3 in normal-weight PCOS subjects are still speculative. However, a potential central role of LH can be suggested. In fact, several studies performed in animals and in men have shown that LH regulates INSL3 gonadal production and secretion. In animal studies, very low expressions of INSL3 were first discovered in the testicular Leydig cells of hpg mouse, a mutant mouse with hypogonadotropic hypogonadism caused by a deletion in the hypothalamic gene encoding for GnRH (34). Thereafter, again in mouse, a strict association between INSL3 up-regulation in the testis and the activation of the pituitary-gonadal axis was described during puberty (35). More recent data obtained in rats showed a direct stimulating effect of LH on INSL3 transcription at ovarian theca and testicular Leydig cells (10), and, in the roe deer, seasonal up-regulation of INSL3 production was shown to be related to LH-dependent differentiation of Leydig cells (36). In humans, it has been reported that patients with hypogonadotropic hypogonadism or gonadotropin suppression by a long-acting GnRH analog had very low INSL3 concentrations (11, 37, 38), which were conversely increased by treatment with human chorionic gonadotropin (11, 37, 38). In addition, recent studies have shown that the progressive increase of circulating INSL3 observed in men during pubertal development was preceded by the increase in LH levels (39).

This study introduces INSL3 within the system of the LH-mediated steroidogenesis and therefore of the ovarian hyperandrogenism in PCOS. This concept is supported by the positive correlation of INSL3 circulating levels with the GnRH agonist-stimulated plasma 17OH-progesterone peak levels, which reflects an increased ovarian androgen secretion, and with the ultrasound ovarian follicle number, an anatomical correlate of ovarian steroidogenic function, in the PCOS group (12). However, the strict relationship between INSL3 circulating levels and the number of small antral follicles within the ovaries cannot exclude the possibility that INSL3 may also exert a paracrine action in the ovary similar to what has been described in the testis, in which INSL3 causes an inhibition of apoptosis of germinal cells (10), therefore producing a trophic activity on folliculogenesis in PCOS women.

Conversely, the positive correlation found between LH and testosterone or the GnRH agonist-stimulated plasma 17OH-progesterone peak levels do not exclude the possibility that INSL3 and ovarian hyperandrogenism could be associated as a consequence of the effect of LH on the ovary.

In conclusion, this study shows for the first time that INSL3 levels in PCOS women are related to LH and ovarian androgenic function, thus suggesting that INSL3 could be considered as a new circulating hormone related to LH-dependent ovarian hyperandrogenism, specifically in normal-weight PCOS women. These findings also introduce new concepts in the pathophysiology of ovarian hyperandrogenism in PCOS, which may partially differ according to the different phenotypes. A better understanding of the role of INSL3 in the regulation of ovarian androgen production is therefore warranted.


   Acknowledgments
 
We thank Dr. Antonio Maria Morselli-Labate for statistical analysis and Ms. Susan West for reviewing the English language of this manuscript.


   Footnotes
 
Disclosure Statement: The authors have nothing to disclose.

First Published Online March 13, 2007

Abbreviations: AUC, Area under the curve; BMI, body mass index; CI, confidence interval; DHEA-S, dehydroepiandrosterone sulfate; FAI, free androgen index; INSL, insulin-like factor; OGTT, oral glucose tolerance text; PCOS, polycystic ovary syndrome.

Received August 3, 2006.

Accepted March 6, 2007.


   References
Top
 Abstract
 Introduction
 Subjects and Methods
 Results
 Discussion
 References
 

  1. Ivell R, Hartung S, Anand-Ivell R 2005 Insulin-like factor 3: where are we now? Ann NY Acad Sci 1041:486–496[Abstract/Free Full Text]
  2. Zimmermann S, Schöttler P, Engel W, Adham IM 1997 Mouse Leydig insulin-like (Ley I-L) gene: structure and expression during testis and ovary development. Mol Reprod Dev 47:30–38[CrossRef][Medline]
  3. Nef S, Parada LF 1999 Cryptorchidism in mice mutant for Insl3. Nat Genet 2:295–299
  4. Zimmermann S, Steding G, Emmen JM, Brikmann AO, Nayernia K, Holstein AF, Engel W, Adham IM 1999 Targeted disruption of the Insl3 gene causes bilateral cryptorchidism. Mol Endocrinol 13:681–691[Abstract/Free Full Text]
  5. Nichols N, Binta H, Fields PA, Drost M, Chang S-M, Ivell R, Fields MJ 2005 Immunohistochemical localization of relaxin-like factor/insulin-like peptide-3 in the bovine corpus luteum. Ann NY Acad Sci 1041:506–509[Abstract/Free Full Text]
  6. Roche PJ, Butkus A, Wintour EM, Tregear G 1996 Structure and expression of Leydig insulin-like peptide mRNA in the sheep. Mol Cell Endocrinol 121:171–177[CrossRef][Medline]
  7. Nef S, Parada LF 1999 Cryptorchidism in mice mutant for Insl3. Nat Genet 2: 295–299
  8. Spanel-Borowski K, Schäfer I, Zimmermann S, Engel W, Adham IM 2001 Increase in final stages of follicular atresia and premature decay of corpora lutea in Insl3-deficient mice. Mol Reprod Dev 58:281–286[CrossRef][Medline]
  9. Irving-Rodgers HF, Bathgate RA, Ivell R, Domagalski R, Rodgers RJ 2002 Dynamic changes in the expression of relaxin-like factor (Insl3), cholesterol side-chain cleavage cytochrome P450, and 3ß-hydroxysteroid dehydrogenase in bovine ovarian follicles during growth and atresia. Biol Reprod 66:934–943[Abstract/Free Full Text]
  10. Kawamura K, Kumagai J, Sudo S, Chun SY, Pisarska M, Morita H, Toppari J, Fu P, Wade JD, Bathgate RAD, Hsueh AJW 2004 Paracrine regulation of mammalian oocyte maturation and male germ cell survival. Proc Natl Acad Sci USA 101:7323–7328[Abstract/Free Full Text]
  11. Foresta C, Bettella A, Vinanzi C, Dabrilli P, Meriggiola MC, Garolla A, Ferlin A 2004 Insulin-like factor 3: a novel circulating hormone of testis origin in humans. J Clin Endocrinol Metab 89:5952–5958[Abstract/Free Full Text]
  12. Ehrmann DA, Barnes RB, Rosenfield RL 1995 Polycystic ovary syndrome as a form of functional ovarian hyperandrogenism due to dysregulation of androgen secretion. Endocr Rev 16:322–353[CrossRef][Medline]
  13. Jonard S, Robert Y, Cortet-Rudelli C, Pigny P, Decanter C, Dewailly D 2003 Ultrasound examination of polycystic ovaries: is it worth counting the follicles? Hum Reprod 18:598–603[Abstract/Free Full Text]
  14. Taylor AE, McCourt B, Martin KA, Anderson EJ, Adams JM, Schoenfeld D, Hall JE 1997 Determinants of abnormal gonadotropin secretion in clinically defined women with polycystic ovary syndrome. J Clin Endocrinol Metab 82:2248–2256[Abstract/Free Full Text]
  15. Morales AJ, Laughlin GA, Butzow T, Maheshwari H, Baumann G, Yen SSC 1996 Insulin, somatotropic, and luteinizing hormone axes in non-obese and obese women with polycystic ovary syndrome: common and distinct features. J Clin Endocrinol Metab 81:2854–2864[Abstract]
  16. Silfen ME, Denburg MR, Manibo AM, Lobo RA, Jaffe R, Ferin M, Levine LS, Oberfield SE 2003 Early endocrine, metabolic, and sonographic characteristics of polycystic ovary syndrome (PCOS): comparison between nonobese and obese adolescents. J Clin Endocrinol Metab 88:4682–4688[Abstract/Free Full Text]
  17. Nestler JE, Jakubowicz DJ, Evans WS, Pasquali R 1998 Effects of metformin on spontaneous and clomiphene-induced ovulation in the polycystic ovary syndrome. N Engl J Med 338:1876–1880[Abstract/Free Full Text]
  18. Ferriman D, Gallwey JD 1961 Clinical assessment of body hair growth in women. J Clin Endocrinol Metab 21:1440–1447[Medline]
  19. Gambineri A, Pelusi C, Genghini S, Morselli-Labate AM, Cacciari M, Pagotto U, Pasquali R 2004 Effect of flutamide and metformin administered alone or in combination in dieting obese women with polycystic ovary syndrome. Clin Endocrinol (Oxf) 60:241–249[CrossRef][Medline]
  20. Zawadzki JK, Dunaif A 1992 Diagnostic criteria for polycystic ovary syndrome: towards a rational approach. In: Dunaif A, Givens JR, Haseltine FP, Merriam GR, eds. Polycystic ovary syndrome. Boston: Blackwell Scientific; 377–384
  21. Pasquali R, Gambineri A, Biscotti D, Vicennati V, Gagliardi L, Colitta D, Fiorini S, Cognini GE, Filicori M, Morselli-Labate AM 2000 Effect of long-term treatment with metformin added to hypocaloric diet on body composition, fat distribution, and androgen and insulin levels in abdominally obese women with and without the polycystic ovary syndrome. J Clin Endocrinol Metab 85:2767–2774[Abstract/Free Full Text]
  22. World Health Organization 2000 Obesity: Preventing and Managing the Global Epidemic, Report of a World Health Organization consultation on obesity. Tech Rep Ser 894. Geneva: World Health Organization
  23. Swanson M, Sauerbrei EE, Cooperberg PL 1981 Medical implications of ultrasonically detected polycystic ovaries. J Clin Ultrasound 9:219–222[Medline]
  24. Balen AH, Laven JS, Tan SL, Dewailly D 2003 Ultrasound assessment of the polycystic ovary: international consensus definitions. Hum Reprod Update 9:505–514[Abstract/Free Full Text]
  25. Pasquali R, Gambineri A, Anconetani B, Vicennati V, Colitta D, Caramelli E, Casimirri F, Morselli-Labate AM 1999 The natural history of the metabolic syndrome in young women with the polycystic ovary syndrome and the effect of long-term oestrogen-progestagen treatment. Clin Endocrinol (Oxf) 50:517–527[CrossRef][Medline]
  26. Vicennati V, Pasquali R 2000 Abnormalities of the hypothalamic-pituitary-adrenal axis in nondepressed women with abdominal obesity and relations with insulin resistance: evidence for a central and peripheral alteration. J Clin Endocrinol Metab 85:4093–4098[Abstract/Free Full Text]
  27. Vermeulen A, Verdonck L, Kaufman JM 1999 A critical evaluation of simple methods for the estimation of free testosterone in serum. J Clin Endocrinol Metab 84:3666–3672[Abstract/Free Full Text]
  28. 1987 Immunoassay: a practical guide. Chan DW, Perlstein MT, eds. New York: Academic Press; 71
  29. Norusis MJ 1990 SPSS/PC + 4.0 base and advanced statistics manuals. Chicago: SPSS
  30. Dixon WJ, Brown MB, Engelman L, Jennrich RI 1990 BMDP statistical software manual. Berkeley, CA: University of California Press
  31. Gambineri A, Pelusi C, Vicennati V, Pagotto U, Pasquali R 2002 Obesity and the polycystic ovary syndrome. Int J Obes Relat Metab Disord 26:883–896[CrossRef][Medline]
  32. Poretsky L, Cataldo NA, Rosenwaks Z, Giudice LC 1999 The insulin-related ovarian regulatory system in health and disease. Endocr Rev 20:535–582[Abstract/Free Full Text]
  33. Ehrmann DA 2005 Polycystic ovary syndrome. N Engl J Med 352:1223–1236[Free Full Text]
  34. Cattanach BM, Iddon CA, Charlton HM, Chiappa SA, Fink G 1977 Gonadotropin releasing hormone deficiency in a mutant mouse with hypogonadism. Nature 269:338–340[CrossRef][Medline]
  35. Balvers M, Spiess AN, Domagalski R, Hunt N, Kilic E, Mukhopadhyay AK, Hanks E, Charlton HM, Ivell R 1998 Relaxin-like factor expression as a marker of differentiation in the mouse testis and ovary. Endocrinology 139:2960–2970[Abstract/Free Full Text]
  36. Hombach-Klonisch S, Schön J, Kehlen A, Blottner S, Klonisch T 2004 Seasonal expression of INSL3 and Lgr8/INSL3 receptor transcripts indicates variable differentiation of Leydig cells in the roe deer testis. Biol Reprod 71:1079–1087[Abstract/Free Full Text]
  37. Bay K, Hartung S, Ivell R, Schumacher M, Jürgensen D, Jorgensen N, Holm M, Skakkebaek NE, Andersson A-M 2005 Insulin-like factor 3 serum levels in 135 normal men and 85 men with testicular disorders: relationship to the luteinizing hormone-testosterone axis. J Clin Endocrinol Metab 90:3410–3418[Abstract/Free Full Text]
  38. Bay K, Matthiesson KL, McLachlan RI, Andersson A-M 2006 The effects of gonadotropin suppression and selective replacement on insulin-like factor 3 secretion in normal adult men. J Clin Endocrinol Metab 91:1108–1111[Abstract/Free Full Text]
  39. Ferlin A, Garolla A, Rigon F, Caldogno LR, Lenzi A, Foresta C 2006 Changes in serum Insulin-like factor 3 (INSL3) during normal male puberty. J Clin Endocrinol Metab 91:3426–3431[Abstract/Free Full Text]




This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
92/6/2066    most recent
Author Manuscript (PDF)
Right arrow Submit a related Letter to the Editor
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Gambineri, A.
Right arrow Articles by Pasquali, R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Gambineri, A.
Right arrow Articles by Pasquali, R.
Related Collections
Right arrow Female Endocrinology

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Endocrinology Endocrine Reviews J. Clin. End. & Metab.
Molecular Endocrinology Recent Prog. Horm. Res. All Endocrine Journals