Insulin-like factor 3 -- a new hormone related to polycystic ovary syndrome?

The aim of this study was to find a correlation between insulin-like factor 3 (INSL3) and androgens: androstenedione (A), free testosterone (fT), and total testosterone (T), in two groups of polycystic ovary syndrome (PCOS) women: those with a body mass index (BMI) lower than 25 kg/m(2) and those with a BMI higher than 25 kg/m(2). The association between INSL3 and other serum parameters: luteinising hormone (LH), follicle-stimulating hormone (FSH), dehydroepiandrosterone sulphate (DHEA-S), sex hormone binding globulin (SHBG) and glucose and insulin were also investigated.

The study group comprised 37 PCOS women aged 27 ± 4 years. The control group consisted of 34 healthy, premenopausal women (aged 24.2 ± 1.2) with regular menses and no signs of hyperandrogenism. There were 27 PCOS women of normal weight (BMI < 25 kg/m(2)), and ten overweight individuals (BMI ≥ 25-30 kg/m(2)). Correlations between level of INSL3 and LH, FSH, T, fT, A, DHEA-S, SHBG, metabolic tests, height, weight, and WHR (waist-to-hip ratio) were also investigated.

PCOS women showed non-significantly higher levels of INSL3 compared to the healthy controls (64.6 ± 27.7 and 62.7 ± 20.0 ng/mL, respectively). However, we identified very strong correlations between INSL3 and androstenedione (r = 0.48, p = 0.0115), and free (r = 0.44, p = 0.0108) and total testosterone (r = 0.46, p = 0.0057) in the PCOS subgroup with a BMI of < 25 kg/m(2). There was no statistically significant correlation between INSL3 and LH in any subject of the PCOS group, nor between INSL3 and FSH, DHEA-S, glucose, basal insulin concentration or HOMA-IR.

We found a positive correlation between INSL3 and androgens in PCOS women, especially those with a BMI of < 25 kg/m(2). This may play a key role in PCOS pathophysiology.