International Journal of

Infertility is currently considered to be a major problem in Iran. According to published articles, one in four Iranian couples is infertile (1). Infertility treatment results in numerous economic losses and mental problems. Polycystic ovary syndrome (PCOS) is the most common cause of infertility (1). In Iran, the prevalence of PCOS is 6%. PCOS is caused by excessive production of luteinizing hormone (LH), which results in the formation of ovarian cysts, hyperandrogenism, hyperinsulinemia, insulin resistance, acne, hirsutism, and obesity (2). Previous studies have shown that women with body weight above or below normal are at high risk of infertility (3). One of the symptoms of PCOS is obesity; thus, in such patients, the expansion of fatty tissue may be the result of greater leptin production. Leptin has a critical role in the control of ovulation (3, 4). Patients with PCOS may experience leptin resistance that ultimately results in infertility (4). Therefore, the aim of this study was to investigate serum and follicular fluid leptin concentrations in infertile women with PCOS.
The study was conducted in accordance with ethical procedures and policies approved by the Ethical Committee of Ahvaz Jondishapour University of Medical Sciences, Ahvaz, Iran and Helsinki Declaration of 1975. Informed consent was obtained from all patients and controls. A case-control study was conducted. The case group consisted of 30 infertile women with PCOS, who were admitted to the Infertility Department of Imam Khomainy Hospital in Ahvaz, Iran. Patients had previously been diagnosed with PCOS and infertility by a specialist via ultrasound and clinical and biochemical findings. The case group was undergoing oocyte retrieval in stimulated cycles for in vitro fertilization (IVF). Our control group consisted of 30 healthy fertile women adjusted for age and body mass index (BMI) with the case group. Subjects with infections, diabetes mellitus, renal failure, and hypertension, anorexia, or digestive tract abnormalities were excluded from the study. Age, body weight, and height were measured and BMI was calculated. On day 14 of their menstrual cycle 5 ml blood was collected from all subjects in both groups. Blood was centrifuged at 2000 rpm for 10 min. Serum was separated and stored at -80^oC until measurement. Using an ultrasound-guided transvaginal needle, human luteinized granulose cells were collected from the ovaries of subjects in the case group. Follicular fluid was frozen immediately in liquid nitrogen and stored at -80^oC. Serum and follicular fluid leptin concentrations were determined by the enzyme linked immunosorbent assay (ELISA). The Biovendor kit was used for measurement of leptin concentrations. The normal range of serum leptin was considered 12-23 (ng/ml) (5).

difference (p=0.56).This study aimed to investigate changes in serum and follicular fluid leptin concentrations among infertile women with PCOS and healthy fertile women. Our study showed no significant relationship between age and leptin concentrations. However, Zhong et al revealed that serum leptin concentrations varied with age. This may be explained by the fact that our study groups were at a pre-menopausal stage, whereas the study group in Zhong et al work consisted of both pre-and post-menopausal women, and the mean age of the study group (45.4±14.8years) was higher than that of our study groups (33.6±2.5 and 30.9±3.7 years). We found a positive correlation between serum leptin concentrations and BMI, which is similar to the findings of Zhong et al (6).
In our investigation, a noticeable correlation was observed between serum leptin concentrations and BMI. This is in accordance with the findings of Pehlivonov et al (7). Leptin originates from fatty tissue; thus, an increase in body fat results in more leptin production (8). Therefore, our results are reasonable. However, a correlation was not observed between follicular fluid leptin concentrations and BMI in the case group. In contrast, Fedorcsak et al reported a positive correlation between these two variables (9). We found positive correlations between serum and follicular fluid concentrations in the case group. Studies by Fedorcsak et al confirm our findings (9). In our study, there was no significant difference between leptin concentrations among the cases and controls; this result is in agreement with the findings of Lu et al (10). Based on our study results, no noticeable changes in serum or follicular fluid leptin concentrations were observed in patients with PCOS. Therefore, infertility in patients with PCOS is not a consequence of changes in leptin concentrations. Studies on the effects of other metabolic factors on infertility in such patients are recommended.
 
Acknowledgements
Authors thank Personnels of Infertility Department of Imam Khomainy Hospital in Ahvaz, Iran for collecting the samples. This work was supported by Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.