The spectrum of androgen excess disorders

Comparing Lean and Obese PCOS in Different PCOS Phenotypes: Evidence That the Body Weight Is More Important than the Rotterdam Phenotype in Influencing the Metabolic Status

Polycystic Ovary Syndrome (PCOS) represents a heterogeneous disorder and, using Rotterdam diagnostic criteria, four main phenotypes (A, B, C, and D) have been distinguished. However, it remains unclear whether lean versus obesity status influences findings in the various phenotypes of women with PCOS. 274 women with PCOS were consecutively assessed. Among these women, there were 149 with phenotype A, 24 with phenotype B, 94 with phenotype C, and 7 with phenotype D. We found normal body weight to be very common (65%) in phenotype C patients, common (43%) in phenotype A and D patients, and less represented (but still 25%) in phenotype B patients. Obesity was common in phenotype B (54%) and phenotype A (33%) patients and uncommon in phenotype C (only 11%) and phenotype D (14%) patients. Obese and lean patients of each phenotype were compared. Compared to the phenotype C PCOS patients, both phenotype A and B patients had higher total testosterone circulating values and higher luteinizing hormone/follicle stimulating hormone (LH/FSH) ratio (p < 0.01) while anti-Mullerian hormone (AMH) levels were higher only in phenotype A PCOS patients. Instead, in the three obese PCOS phenotypes no differences in serum insulin, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) calculation, and lipid blood values were observed. Analysis of data of lean patients gave similar results. Compared to the phenotype C PCOS patients, both phenotype A and B patients had higher total testosterone circulating values and higher LH/FSH ratio (p < 0.01) while AMH levels were higher only in phenotype A PCOS patients. However, no differences were observed in the circulating insulin levels, HOMA-IR calculation, or blood lipids between the three groups of lean PCOS patients. We conclude that Rotterdam phenotypes express the differences between PCOS patients in terms of ovulatory pattern and androgen secretion but fail to differentiate between obese patients with altered metabolic patterns and lean patients with normal metabolic patterns. A new classification of PCOS patients is needed and it should consider the influence of body weight on the metabolic patterns of PCOS patients.

Association Between Sex Hormone Levels and Gut Microbiota Composition and Diversity-A Systematic Review

GOALS/BACKGROUND

Animal studies have highlighted how the microbiota acts in a sex-specific manner with sex hormones demonstrating an association with the composition and diversity of the microbiota. This systematic review aimed to gather the available scientific evidence to explore the association between sex hormones and gut microbiota composition and diversity, in humans.

STUDY

Four bibliographic databases were searched in July 2020 using terms related to "microbiota," "microflora," "sex hormones," "testosterone," and "estrogen." Human studies that investigated the correlation between sex hormones and the microbiota composition or diversity using next-generation sequencing were included.

RESULTS

A total of 10,468 records were screened with 13 studies included in this review. In healthy women, higher estrogen levels were found to be associated with a higher abundance of Bacteroidetes, a lower abundance of Firmicutes, the Ruminococcaceae family and increased diversity. In healthy men, raised testosterone levels positively correlated with Ruminococcus, Acinetobacter, and an increased microbial diversity. Escherichia and Shigella spp. were correlated with raised testosterone in healthy women whereas Ruminococcus spp. was negatively associated with elevated testosterone levels. Women with altered testosterone/estrogen profiles (such as in polycystic ovary syndrome), had a differing gut microbiota compared with healthy women.

CONCLUSIONS

The findings gathered highlight an association between sex hormones and the gut microbiota composition/diversity and may contribute to the sex-based variations observed in disease pathogenesis. Factors such as age and medical conditions are implicated in the associations observed and should be accounted for in future studies. As the understanding of the complex symbiotic relationship between humans and their gut microbiota increases, microbiota modulation could be an attractive option for the prevention and treatment of gastrointestinal disorders.

The role of androgen receptor CAG repeat polymorphism in androgen excess disorder and idiopathic hirsutism

PURPOSE

The study aimed to investigate whether repeat number in the androgen receptor (AR) gene has any contribution to phenotypes of the disease of androgen excess (polycystic ovary syndrome (PCOS), idiopathic hyperandrogenemia (IHA) and idiopathic hirsutism (IH) in a cohort of Turkish women.

METHODS

Three hundred and fifty-four voluntary premenopausal women (172 healthy controls and 182 patients with androgen excess disorders and idiopathic hirsutism) 18-45 years of age seen at an outpatient endocrine clinic at Erciyes University Hospital between January 2013 and December 2014 were included. All volunteers have undergone physical examination and biochemical evaluation. The polymorphic (CAG)n repeat of the human AR was determined by fragment analyses.

RESULTS

Detailed clinical analyses of the patients ended up with 137 PCOS, 24 IHA, and 21 IH. Pairwise comparisons revealed the CAG repeat number differences between the PCOS and controls (p = 0.005) and IH and controls (p = 0.020). Women with CAG repeat length ≤ 17 had a significantly increased twofold risk for PCOS than those women with > 17 CAG repeats OR: 2.0 (95% CI 1.2-3.3, p = 0.005). Women with CAG repeat length ≤ 17 had a significantly increased threefold risk for IH than those women with > 17 CAG repeats OR: 2.9 (95% CI 1.2-7.3, p = 0.020). When correlation analysis was performed, a weak negative correlation was detected between the short allele and FGS score (r = - 0.131, p = 0.013) and a positive relationship between total testosterone and longer allele in the IHA group (r = 0.425, p = 0.039). Median repeat length of the shorter allele between oligomenorrhea and woman with normal menstrual cycle was found to be statistically significant (p = 0.017).

CONCLUSION

This study indicated that the risk of PCOS and IH is associated with the inheritance of ARs with shorter CAG repeats.

Characterization of metabolic changes in the phenotypes of women with polycystic ovary syndrome in a large Mediterranean population from Sicily

OBJECTIVE

To better characterize the metabolic alterations in various phenotypes of polycystic ovary syndrome (PCOS) in a large homogeneous (Sicilian) Mediterranean population with a low prevalence of obesity.

DESIGN

Retrospective study.

PATIENTS

A total of 1215 consecutively evaluated women with PCOS divided into four Rotterdam phenotypes (A, B, C and D) and in 108 matched ovulatory, nonhyperandrogenic women.

MEASUREMENTS

BMI, fasting glucose, total cholesterol, HDL cholesterol, triglycerides, LDL cholesterol and an oral glucose tolerance test.

RESULTS

The overall prevalence of obesity was 31%, metabolic syndrome 6.6%, diabetes 2.1%, altered glucose metabolism 13.1%, and abnormal lipid profile 60%. Phenotype B had the highest prevalence of obesity, metabolic syndrome, altered glucose metabolism and lipid abnormalities compared to other PCOS phenotypes and controls. Phenotype A was more obese and more women had metabolic syndrome compared to phenotypes C and D but phenotype C had a similar prevalence of altered glucose metabolism and lipid abnormalities compared to phenotype A which had a higher BMI. These metabolic abnormalities in A and C were higher compared to phenotype D and controls. Multivariate analysis showed that BMI predicts only abnormalities in fasting glucose and triglycerides, while there was no association with androgens.

CONCLUSIONS

In Mediterranean women with PCOS from Sicily with a lower prevalence of obesity, the prevalence of diabetes, altered glucose metabolism and metabolic syndrome were much lower than reported in US studies. Phenotype B was the most metabolically affected phenotype, followed by phenotype A. Phenotype C had an intermediate disorder but with a high prevalence of altered glucose metabolism and lipid alterations. Only the normoandrogenic phenotype D had no metabolic abnormalities.

Reproductive System Outcome Among Patients with Polycystic Ovarian Syndrome

Polycystic ovarian syndrome (PCOS) may present with different clinical patterns and the anovulatory phenotype may not be the most common. Data suggest that anovulation in PCOS is not the consequence of increased androgen ovarian secretion but rather of a severe derangement of early follicle development. Other mechanisms may be operative in subgroups of patients and may contribute to the arrest of follicle growth and anovulation. At least 50% of anovulatory patients with PCOS become ovulatory in their late reproductive age. There is also evidence that menopause may occur later in women with PCOS. Finally, a strategy for treatment of infertility in PCOS is presented.

Hirsutism: diagnosis and treatment

Hirsutism is defined as excessive terminal hair growth in androgen-dependent areas of the body in women, which grows in a typical male distribution pattern. Hirsutism is a common clinical problem in women, and the treatment depends on the cause. The condition is often associated with a loss of self-esteem. Hirsutism reflects the interaction between circulating androgen concentrations, local androgen concentrations, and the sensitivity of the hair follicle to androgens. Polycystic ovary syndrome and idiopathic hirsutism are the most common causes of the condition. A woman’s history and, physical examination are particularly important in evaluating excess hair growth. The vast majority of women with hirsutism have the idiopathic variety, and the diagnosis is made by exclusion. Serum testosterone level > 200 ng/dL is highly suggestive of adrenal or ovarian tumor. Treatment of hirsutism should be based on the degree of excess hair growth presented by the patient and in the pathophysiology of the disorder. Treatment includes lifestyle therapies, androgen suppression, peripheral androgen blockage, and cosmetic treatments. The current review discusses definition, pathogenesis, physiopathology, differential diagnosis, diagnostic strategies, and treatment.

Therapy in endocrine disease: treatment of hirsutism in the polycystic ovary syndrome

Hirsutism is a common medical complaint among women of reproductive age, and it affects the majority of women with the polycystic ovary syndrome (PCOS). Increased rate of androgen production and its availability in tissue represent the main pathophysiological mechanisms responsible for hirsutism. In addition, androgens may be generated de novo in the hair follicle; therefore, circulating androgen levels do not quantify the real exposure of the hair follicle to androgens, as a quota is locally generated. Hirsutism is a clinical sign and not a disease in itself; its presence does not therefore necessarily require treatment, particularly in mild-to-moderate forms, and when an affected woman does not worry about it. Physicians should decide whether hirsutism is to be treated or not by evaluating not only the severity of the phenomenon but also the subjective perception of the patient, which does not necessarily correspond to the true extent of hair growth. In any case, a physician should manage a woman with hirsutism only on the basis of a diagnosis of the underlying cause, and after a clear explanation of the efficacy of each therapeutic choice. Cosmetic procedures and pharmacological intervention are commonly used in the treatment of hirsutism and are discussed in this paper. Importantly, there are different phenotypes of women with hirsutism and PCOS that may require specific attention in the choice of treatment. In particular, when obesity is present, lifestyle intervention should be always considered, and if necessary combined with pharmacotherapy.

Cardiac autonomic modulation in polycystic ovary syndrome: does the phenotype matter?

OBJECTIVE

To assess whether heart rate variability (HRV) at rest and during sympathetic stimulation is disturbed in patients with different polycystic ovary syndrome (PCOS) phenotypes in comparison to healthy controls.

DESIGN

Cross-sectional study.

SETTING

University hospital.

PATIENT(S)

Thirty women with classic, anovulatory PCOS, 16 women with ovulatory PCOS, and 23 age-paired women with regular and proven ovulatory cycles.

INTERVENTION(S)

Anthropometric and hormonal evaluation and analysis of HRV (time and frequency domain HRV indices) at rest and after a mental stress test.

MAIN OUTCOME MEASURE(S)

Difference between HRV components during rest and stress.

RESULT(S)

Mean age was 22.80 ± 5.80 years in patients with classic PCOS, 19.81 ± 6.43 years in ovulatory PCOS, and 22.65 ± 5.89 years in controls. During mental stress, patients with classic PCOS showed lower HRV response when compared with the control group, even after adjustment for body mass index (BMI) and age. When patients with classic and ovulatory PCOS were considered together, total T levels were inversely associated with the low frequency component, low frequency/high frequency ratio, and the difference between high frequency response at rest and after the stress test.

CONCLUSION(S)

Young patients with the classic PCOS phenotype have an impaired autonomic modulation in response to sympathetic stimulation that is typical of considerably older women, or of advanced age.

Epidemiology, diagnosis and management of hirsutism: a consensus statement by the Androgen Excess and Polycystic Ovary Syndrome Society

BACKGROUND

Hirsutism, defined by the presence of excessive terminal hair in androgen-sensitive areas of the female body, is one of the most common disorders in women during reproductive age.

METHODS

We conducted a systematic review and critical assessment of the available evidence pertaining to the epidemiology, pathophysiology, diagnosis and management of hirsutism.

RESULTS

The prevalence of hirsutism is ~10% in most populations, with the important exception of Far-East Asian women who present hirsutism less frequently. Although usually caused by relatively benign functional conditions, with the polycystic ovary syndrome leading the list of the most frequent etiologies, hirsutism may be the presenting symptom of a life-threatening tumor requiring immediate intervention.

CONCLUSIONS

Following evidence-based diagnostic and treatment strategies that address not only the amelioration of hirsutism but also the treatment of the underlying etiology is essential for the proper management of affected women, especially considering that hirsutism is, in most cases, a chronic disorder needing long-term follow-up. Accordingly, we provide evidence-based guidelines for the etiological diagnosis and for the management of this frequent medical complaint.

Hirsutism: investigation and management

In all hirsute women, a careful diagnostic evaluation should be performed, and the findings will largely influence the therapeutic decisions and the follow-up of the patients. An assay of serum 17-OH progesterone is needed, while the measurement of total testosterone and sex hormone-binding globulin, with the calculation of free androgen index, are useful to assess androgen secretion. Other tests should be suggested only according to responses of specific clinical questions. Owing to their high cardiovascular and metabolic risk, patients with polycystic ovary syndrome should have an oral glucose-tolerance test and a complete lipid profile. No ideal treatment for hirsutism exists but, with careful combination of pharmacological treatments and direct hair removal, it is generally possible to obtain a prolonged improvement of hirsutism.

Milder forms of atherogenic dyslipidemia in ovulatory versus anovulatory polycystic ovary syndrome phenotype

BACKGROUND

Dyslipidemia is common in women with polycystic ovary syndrome (PCOS) but its prevalence in different PCOS phenotypes is still largely unknown.

METHODS

We measured plasma lipids and lipoproteins in 35 anovulatory PCOS (age: 25 +/- 6 years, BMI: 28 +/- 6 kg/m(2)), 15 ovulatory PCOS (age: 30 +/- 6 years, BMI: 25 +/- 3 kg/m(2)) and 27 healthy women (controls) age- and BMI-matched with ovulatory PCOS. PCOS was diagnosed by the presence of clinical or biologic hyperandrogenism associated with chronic anovulation and/or polycystic ovaries at ultrasound. In women with normal menses chronic anovulation was indicated by low serum progesterone levels (<9.54 nmol/l) during midluteal phase (days 21-24) in two consecutive menstrual cycles.

RESULTS

Total cholesterol, triglycerides and low-density lipoprotein (LDL)-cholesterol levels increased and high-density lipoprotein (HDL)-cholesterol decreased from controls to ovulatory and then to anovulatory PCOS (all P < 0.05). Levels of lipoprotein(a) (Lp(a)) and small, dense LDL increased (P < 0.0001 for both) and LDL size reduced (P < 0.005) between groups. Insulin resistance (by HOMA) showed a positive correlation with triglycerides and small, dense LDL and an inverse correlation with HDL-cholesterol and LDL size (P < 0.05 for all) in both PCOS phenotypes. No significant correlations were found with testosterone levels. At multivariate analysis, insulin resistance was independently associated with HDL-cholesterol and small, dense LDL in both PCOS phenotypes and with triglyceride concentrations in ovulatory PCOS only.

CONCLUSIONS

Women with ovulatory PCOS showed milder forms of atherogenic dyslipidemia than anovulatory PCOS and this seemed to be related to the extent of insulin resistance. Future prospective studies are needed to assess the relative contribution of such alterations on cardiovascular risk.

Atherogenic forms of dyslipidaemia in women with polycystic ovary syndrome

OBJECTIVE

Dyslipidaemia is very common in patients with polycystic ovary syndrome (PCOS) but, beyond plasma lipids, atherogenic lipoprotein (Lp) and apolipoprotein (apo) alterations are still ill defined.

DESIGN

We measured concentrations of apoB, Lp(a) and small, dense low-density lipoprotein (LDL) in 42 patients with PCOS [age: 28 +/- 7 years, body mass index (BMI): 27 +/- 5 kg/m(2)] vs. 37 age- and BMI-matched healthy controls.

METHODS

Elevated Lp(a) levels considered were those > 30 mg/dl while elevated apoB concentrations were those > 100 g/l.

RESULTS

Polycystic ovary syndrome showed increased triglycerides levels (p = 0.0011) and lower high-density lipoprotein (HDL)-cholesterol concentrations (p = 0.0131) while total- and LDL cholesterol were similar. PCOS also showed smaller LDL size (p = 0.0005), higher levels of total small, dense LDL (p < 0.0001), higher concentrations of Lp(a), as considered as absolute values (p = 0.0143) and log-transformed (p = 0.0014), while no differences were found in apoB levels. Elevated Lp(a) concentrations were found in 24% of PCOS, while elevated apoB levels were relatively uncommon (14%). Spearman correlation analysis revealed that Lp(a) concentrations were weakly correlated only with HDL-cholesterol levels (r = -0.378, p = 0.0431). In addition, 36% of patients with PCOS with normal plasma lipid profile showed elevated levels of Lp(a), apoB or small, dense LDL.

CONCLUSIONS

Atherogenic Lp abnormalities may be found in one-third of women with PCOS who have a normal lipid pattern. Future prospective studies are needed to test to which extent such atherogenic forms of dyslipidaemia may contribute to the increased cardiovascular risk in young women with PCOS.

Selective impairment in glycogen synthase kinase-3 and mitogen-activated protein kinase phosphorylation: comparisons with the hyperandrogenic and the hyperinsulinemic rats

OBJECTIVE

To characterize and compare the effect of DHEA and insulin plus hCG on ovarian morphology, estrous cycle, hormonal levels, insulin sensitivity, and the regulation of insulin signaling in rats.

DESIGN

Animal model study.

SETTING

University laboratory.

ANIMAL(S)

Female Sprague-Dawley rats.

INTERVENTION(S)

Female rats received DHEA or insulin plus hCG by continuous administration.

MAIN OUTCOME MEASURE(S)

Ovarian morphology, estrous cycle, hormonal levels, insulin sensitivity, protein levels, and phosphorylation state of glycogen synthase kinase-3beta and extracellular regulated kinase 1/2 in the ovary.

RESULT(S)

Rats treated with DHEA displayed anovulation, insulin resistance, and polycystic ovaries characterized by cysts and a diminished granulosa layer. In contrast, insulin plus hCG results in acyclicity with increasing androgen biosynthesis and ovarian morphology different from that in DHEA-treated rats. Moreover, we found that insulin-stimulated serine-phosphorylation of glycogen synthase kinase-3beta was higher in insulin plus hCG-treated rats but lower in DHEA-treated rats. Furthermore, basal and insulin-stimulated tyrosine-phosphorylation of extracellular regulated kinase 1/2 was higher in DHEA-treated rats than in controls.

CONCLUSION(S)

Notwithstanding that both the hyperandrogenism and the hyperinsulinemia synergistic with hCG-treated rats displayed the typical traits of human polycystic ovary syndrome, there is a divergence in the insulin-signaling pathway in the ovarian tissue, which may have a role in the pathogenesis of polycystic ovary syndrome.

Idiopathic hirsutism: excessive bodily and facial hair in women

Hirsutism is the excessive and increased bodily and facial hair growth in women in locations where hair is normally minimal or absent. It refers to the growth of hair in a pattern normally occurring only in men, and therefore primarily raises psychological, cosmetic and social concerns. Idiopathic hirsutism (IH), where the cause of excessive hair growth is unknown, is considered to be the most common form of hirsutism. It is suspected that this type of hirsutism may be familial, as there is often a family history of the condition. Women with IH will generally have normal menses and normal levels of testosterone. There are many treatment modalities that fall into two broad groups: medical and mechanical treatment. An example of a medical treatment is when an agent is used, which interferes with the synthesis of androgen at the ovarian or adrenal level, or by inhibiting the effect of androgen at the receptor level. An example of a mechanical treatment is laser hair removal, where the hair follicle is destroyed; however, much depends on the on the skill of the treating practitioner, laser type, laser spot size, skin type, hair colour, and the stage at which the hair follicles were during their hair growth cycle, and the delivered wavelength. Laser offers the fastest method of hair loss. Other mechanical treatments include electrolysis, depilatory creams, plucking and waxing. This article presents a general overview of IH, including a definition, diagnostic measures, clinical manifestations, normal and abnormal physiology, and treatment options.

Adrenarche and polycystic ovary syndrome: a tale of two hypotheses

Polycystic ovary syndrome (PCOS) is an extremely common endocrine disorder affecting young women, with the potential for both reproductive and non-reproductive adverse outcomes. While oligomenorrhea, hyperandrogenism, and cystic ovarian morphology are recognized characteristics of this syndrome, the origin of these disturbances is not always apparent. During normal growth and development, adrenarche, the prepubertal onset of adrenal androgen secretion, results phenotypically in pubarche. Gonadarche, which is the ovarian response to gonadotropin releasing hormone-mediated gonadotropin secretion, also occurs, leading to reproductive competence, namely the establishment of ovulatory cycles, repeatedly. In this mini-review, an overview of adrenarche and gonadarche are presented, followed by two hypotheses. The first describes an evolutionary role for adrenarche: an advantage in the attainment of reproductive competence. The second proposes that the path to PCOS be viewed from a developmental perspective, namely, that PCOS is a maladaptation of the processes that lead to reproductive competence in women. Its defining characteristics of oligomenorrhea, hyperandrogenism, and cystic ovarian morphology are the final common pathway of multiple possible derangements. Elucidating and understanding these maladaptive processes will be the key to future endeavors at prevention and treatment of this common reproductive disorder.

Characteristics of different phenotypes of polycystic ovary syndrome in a Bulgarian population

AIM

Our aim was to investigate the percentage occurrence of different phenotypes of polycystic ovary syndrome (PCOS) in a Bulgarian population, and their clinical, biochemical and hormonal characteristics.

METHODS

The study included 70 women with PCOS, diagnosed according to the European Society of Human Reproduction & Embryology/American Society for Reproductive Medicine criteria. The women were divided into four phenotypes: hyperandrogenism (HA) + oligo-/anovulation (OA) + polycystic ovaries at ultrasound (PCO) (full-blown syndrome, phenotype A); HA + OA (former National Institutes of Health definition, phenotype B); OA + PCO (phenotype C); and HA + PCO (phenotype D). Serum levels of testosterone, immune-reactive insulin, sex hormone-binding globulin, dehydroepiandrosterone sulfate and lipid metabolism parameters were measured. Free androgen index and homeostasis model assessment of insulin resistance were calculated. Body mass index and waist-to-hip ratio were assessed.

RESULTS

The percentages of phenotypes A, B, C and D in a Bulgarian population are 58.6%, 11.4%, 10.0% and 20.0%, respectively. The women with the classical form of PCOS (phenotypes A and B) were more obese, had more strongly expressed hyperandrogenemia, and were more insulin-resistant compared with the women of phenotypes C and D.

CONCLUSION

There is a significant difference in anthropometric, hormonal and metabolic indices between the classical form and the clinical variants of PCOS in the studied Bulgarian population.

Prevalence and metabolic characteristics of adrenal androgen excess in hyperandrogenic women with different phenotypes

BACKGROUND

Serum DHEAS has been found to be elevated in some women with polycystic ovary syndrome (PCOS). We wished to determine whether this prevalence is different in women with androgen excess who have different phenotypes and to correlate these findings with various cardiovascular and metabolic parameters.

METHODS

Two hundred and thirty-eight young hyperandrogenic women categorized into various diagnostic groups were evaluated for elevations in serum DHEAS, testosterone, glucose, insulin, quantitative insulin-sensitivity check index (QUICKI), cholesterol, HDL-C, LDL-C, triglycerides and C-reactive protein (CRP). Data were stratified based on elevations in DHEAS.

RESULTS

Serum DHEAS was elevated in 39.5% for the entire group [36.7% in PCOS and 48.3% in idiopathic hyperandrogenism (IHA)]. In classic (C)-PCOS, the prevalence was 39.6% and in ovulatory (OV) PCOS it was 29.1%. These differences were not statistically significant. Women with elevated DHEAS had higher testosterone but lower insulin, higher QUICKI, lower total and LDL-cholesterol and higher HDL-cholesterol, p<0.01. Triglycerides and CRP were not different. This trend was greatest in women with C-PCOS.

CONCLUSIONS

The prevalence of adrenal hyperandrogenism, as determined by elevations in DHEAS, appears to be statistically similar in IHA, C-PCOS and compared to OV-PCOS. Metabolic and cardiovascular parameters were noted to be more favorable in those women who have higher DHEAS levels.

Age-dependent bimodal GDNF regulation during ovarian tumorigenesis in follitropin receptor mutant mice

Most ovarian tumors in women occur upon aging. Follitropin receptor knockout (FORKO) mice are sterile and have age-dependent abnormalities including increased ovarian tumor incidence. To explore why atrophic ovaries of FORKO mice become tumorigenic later in life, we compared gene expression profiles by microarray at different ages. Here we show an unexpected ovarian expression of GDNF and its bimodal regulation. GDNF was down-regulated at a young age but up-regulated in aging FORKO mice prior to tumor appearance. Immunohistochemistry localized GDNF in the oocyte as well as somatic granulosa and stromal cells. GDNF protein also showed an age-dependent increase in the ovary, being lower in young mutants and increasing by 6 months. We found evidence for GDNF up-regulation in GC tumors and a potential role for androgen. The peripheral expression pattern and functions of this powerful neurotropic factor suggest mediation of processes involved in pathology of ovarian compartments.