Correlation of insulin resistance with male reproductive hormone levels and semen parameters

Objective To investigate the influence of insulin resistance on male reproductive hormones and semen quality. METHODS Using the electrochemiluminescence method, we measured the levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), estradiol (E2) and testosterone (T) in the serum of 83 infertile males. We detected the levels of fasting plasma glucose (FPG) and fasting insulin (FINS) and calculated the insulin resistance index presented as homeostasis model assessment of insulin resistance (HOMA-IR). Based on HOMA-IR, we divided the patients into three tertile groups, T1 (HOMA-IR 0.36－0.55, n = 27), T2 (HOMA-IR 0.56－0.80, n = 28) and T3 (HOMA-IR 0.81－1.97, n = 28), obtained their semen parameters by computer-assisted semen analysis (CASA) and analyzed the correlation of HOMA-IR with male reproductive hormone levels and semen parameters. RESULTS With the elevation of HOMA-IR, the patients of the T1, T2 and T3 groups showed significant decreases in the serum T level (［14,26 ± 4.27］ vs ［14.75 ± 5.00］ vs ［11.62 ± 3.68］ nmol/L, P <0.05) and the percentage of progressively motile sperm (PMS) (［51.04 ± 15.10］% vs ［48.04 ± 16.24］% vs ［37.84 ± 18.23］%, P <0.05). HOMA-IR was correlated negatively with the serum T level (r = －0.333, P = 0.002), semen volume (r = －0.23, P = 0.029) and PMS (r = －0.27, P = 0.015), and so was FINS with the serum T level (r = －0.327, P = 0.003) and PMS (r = －0.315, P = 0.004), while the semen volume was correlated positively with the levels of serum T (r = 0.221, P = 0.048) and FSH (r = 0.222, P = 0.047). Multivariate linear regression analysis showed that HOMA-IR was an independent influencing factor for PMS and the body mass index (BMI) was that for the semen volume and total sperm count. CONCLUSIONS Insulin resistance may reduce semen quality by changing the levels of male reproductive hormones.