Endocrine Abstracts

Background: A minority of women with polycystic ovary syndrome (PCOS) is lean, and several individuals have no signs of hyperandrogenaemia. Earlier we showed that lean PCOS patients have no increased visceral adiposity. The aim of the present study was study is to characterize the metabolic and hormonal status a group of lean PCOS cases.

Methods: In this cross-sectional study ten Caucasian women with PCOS and ten controls carefully matched for age and BMI were studied. Mean age was 31±2 years, and all had BMI between 19 and 25 kg/m² and similar total fat contents, according to bioelectrical impedance analysis (BIA) and magnetic resonance imaging (MRI). Glucose, insulin, testosterone, SHBG, gonadotrophins, anti-Müllerian hormone (AMH), inhibin B and adipokines (adiponectin, leptin, TNF-α, IL6 and RBP-4) were assessed by standard techniques.

Results: BMI’s were 21.6±1.1 vs 21.8±2.1 kg/m², waist-hip ratios 0.83±0.07 vs 0.85±0.03, fat mass 13.2 (4.9–19.7) vs 14.4 (4.0–22.5) kg and lean body mass 52.4 (45.2–59.4) vs 53.4 (44.4–59.7) kg for PCOS and control women, respectively (all P=NS). Fasting blood glucose and insulin levels were similar, and HOMA-IR was 0.55±0.19 and 0.63±0.18. Also the levels of adipokines were similar between both groups. PCOS cases had significant higher free androgen index (FAI), lower estradiol and lower FSH, but similar inhibin B. AMH levels were 11.1±3.0 ng/ml in PCOS vs 3.3±1.8 ng/ml in controls (P<0.01). Pooled ovarian volumes correlated positively with AMH levels, calculated for the largest ovary of each individual (r=0.75, P<0.0001) vs the smallest ovary (r=0.70, P<0.001), while positive correlations were only demonstrated between Inhibin B levels and the largest ovaries (r=0.58, P<0.01).

Conclusions: We observed no differences in metabolic parameters and insulin resistance between lean PCOS cases vs controls. Also in lean PCOS patients, AMH levels are increased. Similar ovarian-AMH relationships but different volume-inhibin B relationships confirm that both hormones originate from different ovarian cells (early antral vs granulosa cells). The differences in FSH need to be explored further.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.